Merge ~cjwatson/lazr.restful:manual-pyupgrade into lazr.restful:main

[Colin Watson]

Apply some more pyupgrade-like changes

pyupgrade itself missed these either because they were in doctests or due to cautiousness.

[Jürgen Gmach (jugmac00)]

review: Approve

diff --git a/src/lazr/restful/_bytestorage.py b/src/lazr/restful/_bytestorage.py
index b25369c..45c6f2d 100644
--- a/src/lazr/restful/_bytestorage.py
+++ b/src/lazr/restful/_bytestorage.py
@@ -62,7 +62,7 @@ class ByteStorageResource(HTTPResource):
         """See `IByteStorageResource`."""
         media_type = self.getPreferredSupportedContentType()
         if media_type in [self.WADL_TYPE, self.DEPRECATED_WADL_TYPE]:
-            result = self.toWADL().encode("utf-8")
+            result = self.toWADL().encode()
             self.request.response.setHeader("Content-Type", media_type)
             return result
         if not self.context.is_stored:
diff --git a/src/lazr/restful/_resource.py b/src/lazr/restful/_resource.py
index 2d4a486..89c005b 100644
--- a/src/lazr/restful/_resource.py
+++ b/src/lazr/restful/_resource.py
@@ -435,9 +435,9 @@ class HTTPResource:
 
         # Append the media type, so that web browsers won't treat
         # different representations of a resource interchangeably.
-        core_hashes[-1].update(("\0" + media_type).encode("UTF-8"))
+        core_hashes[-1].update(("\0" + media_type).encode())
 
-        etag = '"%s"' % "-".join([core.hexdigest() for core in core_hashes])
+        etag = '"%s"' % "-".join(core.hexdigest() for core in core_hashes)
         self.etags_by_media_type[media_type] = etag
         return etag
 
@@ -1144,7 +1144,7 @@ class EntryManipulatingResource(ReadWriteResource):
                 # storage resource as a str, but
                 # BytesFieldMarshaller.marshall_from_json_data returns
                 # bytes.
-                if value != current_value.encode("UTF-8"):
+                if value != current_value.encode():
                     if field.readonly:
                         errors.append(modified_read_only_attribute % repr_name)
                     else:
@@ -1279,7 +1279,7 @@ class EntryManipulatingResource(ReadWriteResource):
             self.request.response.setStatus(209)
             media_type = self.getPreferredSupportedContentType()
             self.request.response.setHeader("Content-type", media_type)
-            return self._representation(media_type).encode("UTF-8")
+            return self._representation(media_type).encode()
         else:
             # The object moved. Serve a redirect to its new location.
             # This might not necessarily be the location of the entry!
@@ -1319,7 +1319,7 @@ class EntryFieldResource(FieldUnmarshallerMixin, EntryManipulatingResource):
             return b""
         else:
             self.request.response.setHeader("Content-Type", media_type)
-            return self._representation(media_type).encode("UTF-8")
+            return self._representation(media_type).encode()
 
     def do_PUT(self, media_type, representation):
         """Overwrite the field's existing value with a new value."""
@@ -1344,7 +1344,7 @@ class EntryFieldResource(FieldUnmarshallerMixin, EntryManipulatingResource):
         # generating the representation might itself change across
         # versions.
         revno = getUtility(IWebServiceConfiguration).code_revision
-        return [core.encode("utf-8") for core in [revno, str(value)]]
+        return [core.encode() for core in [revno, str(value)]]
 
     def _representation(self, media_type):
         """Create a representation of the field value."""
@@ -1408,8 +1408,8 @@ def make_entry_etag_cores(field_details):
             bucket = unwritable_values
         bucket.append(decode_value(details["value"]))
 
-    unwritable = "\0".join(unwritable_values).encode("utf-8")
-    writable = "\0".join(writable_values).encode("utf-8")
+    unwritable = "\0".join(unwritable_values).encode()
+    writable = "\0".join(writable_values).encode()
     return [unwritable, writable]
 
 
@@ -1608,7 +1608,7 @@ class EntryResource(
                 return b""
             else:
                 self.request.response.setHeader("Content-Type", media_type)
-                return self._representation(media_type).encode("UTF-8")
+                return self._representation(media_type).encode()
 
     def do_PUT(self, media_type, representation):
         """Modify the entry's state to match the given representation.
@@ -1940,7 +1940,7 @@ class ServiceRootResource(HTTPResource):
         itself changes.
         """
         revno = getUtility(IWebServiceConfiguration).code_revision
-        return [revno.encode("utf-8")]
+        return [revno.encode()]
 
     def __call__(self, REQUEST=None):
         """Handle a GET request."""
diff --git a/src/lazr/restful/docs/checker-utilities.rst b/src/lazr/restful/docs/checker-utilities.rst
index 56ad615..1836f02 100644
--- a/src/lazr/restful/docs/checker-utilities.rst
+++ b/src/lazr/restful/docs/checker-utilities.rst
@@ -15,18 +15,18 @@ the schema passed in as parameter.
     >>> from zope.schema import TextLine
 
     >>> class MySchema(Interface):
-    ...     an_attr = Attribute(u'An attribute.')
+    ...     an_attr = Attribute('An attribute.')
     ...
-    ...     a_field = TextLine(title=u'A property that can be set.')
+    ...     a_field = TextLine(title='A property that can be set.')
     ...
     ...     a_read_only_field = TextLine(
-    ...         title=u'A read only property', readonly=True)
+    ...         title='A read only property', readonly=True)
     ...
     ...     def aMethod():
     ...         "A simple method."
 
     >>> @implementer(MySchema)
-    ... class MyContent(object):
+    ... class MyContent:
     ...     def __init__(self, an_attr, a_field, a_read_only_field):
     ...         self.an_attr = an_attr
     ...         self.a_field = a_field
@@ -42,7 +42,7 @@ attributes defined in the schema.
 
     >>> from lazr.restful.debug import debug_proxy
     >>> from zope.security.checker import undefineChecker, ProxyFactory
-    >>> content = MyContent(1, u'Mutable Field', u'RO Field')
+    >>> content = MyContent(1, 'Mutable Field', 'RO Field')
 
 ProxyFactory wraps the content using the defined checker.
 
diff --git a/src/lazr/restful/docs/django.rst b/src/lazr/restful/docs/django.rst
index 2ad1df2..503737c 100644
--- a/src/lazr/restful/docs/django.rst
+++ b/src/lazr/restful/docs/django.rst
@@ -43,7 +43,7 @@ sorts of Django code that we can't handle.
     >>> import django.core.exceptions
     >>> django.core.exceptions.ObjectDoesNotExist = ObjectDoesNotExist
 
-    >>> class Manager(object):
+    >>> class Manager:
     ...     """A fake version of Django's Manager class."""
     ...     def __init__(self, l):
     ...         self.list = l
diff --git a/src/lazr/restful/docs/fields.rst b/src/lazr/restful/docs/fields.rst
index a91761f..869eb20 100644
--- a/src/lazr/restful/docs/fields.rst
+++ b/src/lazr/restful/docs/fields.rst
@@ -14,7 +14,7 @@ field provides ICollectionField which is an extension of ISequence.
     >>> from lazr.restful.fields import CollectionField
 
     >>> int_collection = CollectionField(
-    ...     title=u'A collection', value_type=Int())
+    ...     title='A collection', value_type=Int())
 
     >>> from zope.interface.verify import verifyObject
     >>> verifyObject(ICollectionField, int_collection)
@@ -31,7 +31,7 @@ By default, such fields are readonly.
 But it can be made read-write.
 
     >>> rw_collection = CollectionField(
-    ...     title=u'A writable collection.', readonly=False)
+    ...     title='A writable collection.', readonly=False)
     >>> rw_collection.readonly
     False
 
@@ -75,7 +75,7 @@ by value, but only check that the value provides the proper schema.
     >>> verifyObject(IReference, reference)
     True
 
-    >>> class Fake(object):
+    >>> class Fake:
     ...     pass
     >>> fake = Fake()
     >>> reference.validate(fake)
diff --git a/src/lazr/restful/docs/interface.rst b/src/lazr/restful/docs/interface.rst
index a2d100e..afcd439 100644
--- a/src/lazr/restful/docs/interface.rst
+++ b/src/lazr/restful/docs/interface.rst
@@ -26,13 +26,13 @@ Let's define a "model" schema:
     >>> class MyModel(Interface):
     ...     """A very simple model."""
     ...
-    ...     age = Int(title=u"Number of years since birth")
-    ...     name = Text(title=u"Identifier")
+    ...     age = Int(title="Number of years since birth")
+    ...     name = Text(title="Identifier")
 
     >>> class Initiated(MyModel):
     ...     illuminated = Choice(
-    ...         title=u"Has seen the fnords?", values=('yes', 'no', 'maybe'))
-    ...     fancy_value = Attribute(u"Some other fancy value.")
+    ...         title="Has seen the fnords?", values=('yes', 'no', 'maybe'))
+    ...     fancy_value = Attribute("Some other fancy value.")
 
 The use_template() helper takes as first parameter the interface to use
 as a template and either a 'include' or 'exclude' parameter taking the
@@ -44,8 +44,8 @@ So to create a form for UI with more appropriate labels you would use:
     >>> class MyForm1(Interface):
     ...     "Form schema for a MyModel."
     ...     use_template(MyModel, include=['age', 'name'])
-    ...     age.title = u'Your age:'
-    ...     name.title = u'Your name:'
+    ...     age.title = 'Your age:'
+    ...     name.title = 'Your name:'
 
 The MyForm1 interface now has an age and name fields that have a
 distinct titles than their original:
@@ -157,7 +157,7 @@ schema field and override some of the copy attributes at the same time.
 
     >>> from lazr.restful.interface import copy_field
     >>> age = copy_field(
-    ...     MyModel['age'], title=u'The age.', required=False,
+    ...     MyModel['age'], title='The age.', required=False,
     ...     arbitrary=1)
     >>> age.__class__.__name__
     'Int'
diff --git a/src/lazr/restful/docs/multiversion.rst b/src/lazr/restful/docs/multiversion.rst
index 8a3faca..baeef02 100644
--- a/src/lazr/restful/docs/multiversion.rst
+++ b/src/lazr/restful/docs/multiversion.rst
@@ -135,17 +135,13 @@ Now let's define the data model. The model in webservice.txt is
 pretty complicated; this model will be just complicated enough to
 illustrate how to publish multiple versions of a web service.
 
-All classes defined in this test are new-style classes.
-
-    >>> __metaclass__ = type
-
     >>> from zope.interface import Interface, Attribute
     >>> from zope.schema import Bool, Bytes, Int, Text, TextLine, Object
 
     >>> class IContact(Interface):
-    ...     name = TextLine(title=u"Name", required=True)
-    ...     phone = TextLine(title=u"Phone number", required=True)
-    ...     fax = TextLine(title=u"Fax number", required=False)
+    ...     name = TextLine(title="Name", required=True)
+    ...     phone = TextLine(title="Phone number", required=True)
+    ...     fax = TextLine(title="Fax number", required=False)
 
 Here's an interface for the 'set' object that manages the
 contacts.
@@ -267,9 +263,9 @@ The "1.0" version publishes the IContact interface as is, but renames
 two of the fields.
 
     >>> class IContactEntry10(IContactEntry):
-    ...     name = TextLine(title=u"Name", required=True)
-    ...     phone_number = TextLine(title=u"Phone number", required=True)
-    ...     fax_number = TextLine(title=u"Fax number", required=False)
+    ...     name = TextLine(title="Name", required=True)
+    ...     phone_number = TextLine(title="Phone number", required=True)
+    ...     fax_number = TextLine(title="Fax number", required=False)
     ...     taggedValue(LAZR_WEBSERVICE_NAME,
     ...                 dict(singular="contact", plural="contacts"))
 
@@ -290,8 +286,8 @@ The "dev" version drops the "fax_number" field because fax machines
 are obsolete.
 
     >>> class IContactEntryDev(IContactEntry):
-    ...     name = TextLine(title=u"Name", required=True)
-    ...     phone_number = TextLine(title=u"Phone number", required=True)
+    ...     name = TextLine(title="Name", required=True)
+    ...     phone_number = TextLine(title="Phone number", required=True)
     ...     taggedValue(LAZR_WEBSERVICE_NAME,
     ...                 dict(singular="contact", plural="contacts"))
     >>> IContactEntryDev['phone_number'].setTaggedValue(
diff --git a/src/lazr/restful/docs/utils.rst b/src/lazr/restful/docs/utils.rst
index 82cdf43..ea1636a 100644
--- a/src/lazr/restful/docs/utils.rst
+++ b/src/lazr/restful/docs/utils.rst
@@ -179,8 +179,8 @@ that implements as much of the interface as possible.
     >>> from zope.schema import TextLine
     >>> from zope.interface import Interface
     >>> class ITwoFields(Interface):
-    ...     field_1 = TextLine(title=u"field 1", default=u"field_1 default")
-    ...     field_2 = TextLine(title=u"field 2")
+    ...     field_1 = TextLine(title="field 1", default="field_1 default")
+    ...     field_2 = TextLine(title="field 2")
     ...     def a_method():
     ...         pass
 
@@ -233,7 +233,7 @@ not define that attribute.
 The 'superclass' argument lets you specify a superclass for the
 generated class.
 
-    >>> class TwoFieldsSuperclass(object):
+    >>> class TwoFieldsSuperclass:
     ...     def a_method(self):
     ...         return "superclass result"
 
@@ -302,7 +302,7 @@ makes problems harder to diagnose.
     >>> import sys
     >>> from lazr.restful.utils import safe_hasattr
 
-    >>> class Oracle(object):
+    >>> class Oracle:
     ...     @property
     ...     def is_full_moon(self):
     ...         return full_moon
diff --git a/src/lazr/restful/docs/webservice-declarations.rst b/src/lazr/restful/docs/webservice-declarations.rst
index 8c66e30..447aa49 100644
--- a/src/lazr/restful/docs/webservice-declarations.rst
+++ b/src/lazr/restful/docs/webservice-declarations.rst
@@ -41,15 +41,15 @@ field, but not the inventory_number field.
     ... class IBook(Interface):
     ...     """A simple book data model."""
     ...
-    ...     title = exported(TextLine(title=u'The book title'))
+    ...     title = exported(TextLine(title='The book title'))
     ...
-    ...     author = exported(TextLine(title=u"The book's author."))
+    ...     author = exported(TextLine(title="The book's author."))
     ...
     ...     base_price = exported(Float(
-    ...         title=u"The regular price of the book."),
+    ...         title="The regular price of the book."),
     ...         exported_as='price')
     ...
-    ...     inventory_number = TextLine(title=u'The inventory part number.')
+    ...     inventory_number = TextLine(title='The inventory part number.')
 
 These declarations add tagged values to the original interface elements.
 The tags are in the lazr.restful namespace and are dictionaries of
@@ -125,7 +125,7 @@ In the same vein, exported_as_webservice_entry() can only be used on
 Interface.
 
     >>> @exported_as_webservice_entry()
-    ... class NotAnInterface(object):
+    ... class NotAnInterface:
     ...     pass
     Traceback (most recent call last):
       ...
@@ -144,7 +144,7 @@ this by passing in False for the `publish_web_link` argument to
     >>> from zope.interface import Attribute
     >>> @exported_as_webservice_entry(publish_web_link=False)
     ... class INotOnTheWebsite(Interface):
-    ...     field = exported(TextLine(title=u"A field."))
+    ...     field = exported(TextLine(title="A field."))
     >>> print_export_tag(INotOnTheWebsite)
     _as_of_was_used: False
     contributes_to: None
@@ -161,7 +161,7 @@ items:
 
     >>> class ISimpleComment(Interface):
     ...     """A simple comment."""
-    ...     comment = TextLine(title=u'Comment')
+    ...     comment = TextLine(title='Comment')
 
     >>> from zope.schema import Object
     >>> from lazr.restful.fields import CollectionField
@@ -269,7 +269,7 @@ As it is an error, to mark more than one method:
 exported_as_webservice_collection() can only be used on Interface.
 
     >>> @exported_as_webservice_collection(ISampleInterface)
-    ... class NotAnInterface(object):
+    ... class NotAnInterface:
     ...     pass
     Traceback (most recent call last):
       ...
@@ -347,14 +347,14 @@ operation returns a collection of entries.
     ...
     ...     @collection_default_content()
     ...     @operation_parameters(
-    ...         text=copy_field(IBook['title'], title=u'Text to search for.'))
+    ...         text=copy_field(IBook['title'], title='Text to search for.'))
     ...     @operation_returns_collection_of(IBook)
     ...     @export_read_operation()
     ...     def searchBookTitles(text):
     ...         """Return list of books whose titles contain 'text'."""
     ...
     ...     @operation_parameters(
-    ...         text=copy_field(IBook['title'], title=u'Text to search for.'))
+    ...         text=copy_field(IBook['title'], title='Text to search for.'))
     ...     @operation_returns_entry(IBook)
     ...     @export_read_operation()
     ...     def bestMatch(text):
@@ -481,7 +481,7 @@ on the method signature.
     ... class ComplexParameterDefinition(Interface):
     ...     @operation_parameters(
     ...         required1=TextLine(),
-    ...         required2=TextLine(default=u'Not required'),
+    ...         required2=TextLine(default='Not required'),
     ...         optional1=TextLine(required=True),
     ...         optional2=TextLine(),
     ...         )
@@ -792,7 +792,7 @@ we can have an IDeveloper interface contributing to IUser.
     >>> @exported_as_webservice_entry(contributes_to=[IUser])
     ... class IDeveloper(Interface):
     ...     programming_languages = exported(List(
-    ...         title=u'Programming Languages spoken by this developer'))
+    ...         title='Programming Languages spoken by this developer'))
 
 This will cause all the fields/methods of IDeveloper to be exported as part of
 the IBook entry instead of exporting a new entry for IDeveloper. For this to
@@ -996,7 +996,7 @@ interface, and proxies all attributes to the underlying object.
     >>> from zope.interface.verify import verifyObject
     >>> from zope.interface import implementer
     >>> @implementer(IBook)
-    ... class Book(object):
+    ... class Book:
     ...     """Simple IBook implementation."""
     ...     def __init__(self, author, title, base_price,
     ...                  inventory_number):
@@ -1009,7 +1009,7 @@ Now we can turn a Book object into something that implements
 IBookEntry.
 
     >>> entry_adapter = entry_adapter_factory(
-    ...     Book(u'Aldous Huxley', u'Island', 10.0, '12345'),
+    ...     Book('Aldous Huxley', 'Island', 10.0, '12345'),
     ...     request)
 
     >>> entry_adapter.schema is entry_interface
@@ -1059,7 +1059,7 @@ The find() method will return the result of calling the method tagged
 with the @collection_default_content decorator.
 
     >>> @implementer(IBookSet)
-    ... class BookSet(object):
+    ... class BookSet:
     ...     """Simple IBookSet implementation."""
     ...
     ...     def __init__(self, books=()):
@@ -1087,7 +1087,7 @@ find(). The REQUEST_USER marker value will be replaced by the logged in
 user.
 
     >>> @implementer(ICheckedOutBookSet)
-    ... class CheckedOutBookSet(object):
+    ... class CheckedOutBookSet:
     ...     """Simple ICheckedOutBookSet implementation."""
     ...
     ...     def getByTitle(self, title, user):
@@ -1278,7 +1278,7 @@ adapter and set the request as the current interaction.)
     >>> from zope.traversing.browser.interfaces import IAbsoluteURL
     >>> from zope.publisher.interfaces.http import IHTTPApplicationRequest
     >>> @implementer(IAbsoluteURL)
-    ... class BookAbsoluteURL(object):
+    ... class BookAbsoluteURL:
     ...     """Returns a believable absolute URL for a book."""
     ...
     ...     def __init__(self, context, request):
@@ -1417,7 +1417,7 @@ The implementation of set_text() applies a standardized transform to the
 incoming text.
 
     >>> @implementer(IHasText)
-    ... class HasText(object):
+    ... class HasText:
     ...
     ...     def __init__(self):
     ...         self.text = ''
@@ -1580,7 +1580,7 @@ call methods that declare at least one of the corresponding scopes.
     ...         pass
 
     >>> @implementer(IScopedEntry)
-    ... class ScopedEntry(object):
+    ... class ScopedEntry:
     ...
     ...     value = 'initial'
     ...
@@ -2764,7 +2764,7 @@ After the registration, adapters from IBook to IEntry, and IBookSet to
 ICollection are available:
 
     >>> from zope.component import getMultiAdapter
-    >>> book = Book(u'George Orwell', u'1984', 10.0, u'12345-1984')
+    >>> book = Book('George Orwell', '1984', 10.0, '12345-1984')
     >>> bookset = BookSet([book])
 
     >>> entry_adapter = getMultiAdapter((book, request), IEntry)
diff --git a/src/lazr/restful/docs/webservice.rst b/src/lazr/restful/docs/webservice.rst
index 5289633..411d9e8 100644
--- a/src/lazr/restful/docs/webservice.rst
+++ b/src/lazr/restful/docs/webservice.rst
@@ -18,10 +18,6 @@ cookbook contains multiple recipes. A recipe is a recipe _for_ a dish,
 and two or more cookbooks may provide different recipes for the same
 dish. Users may comment on cookbooks and on individual recipes.
 
-All classes defined in this test are new-style classes.
-
-    >>> __metaclass__ = type
-
     >>> from zope.interface import Interface, Attribute
     >>> from zope.schema import Bool, Bytes, Int, Text, TextLine
     >>> from lazr.restful.fields import Reference
@@ -32,7 +28,7 @@ All classes defined in this test are new-style classes.
     ...                      "Defined here for simplicity of testing.")
 
     >>> class IAuthor(ITestDataObject):
-    ...     name = TextLine(title=u"Name", required=True)
+    ...     name = TextLine(title="Name", required=True)
     ...     # favorite_recipe.schema will be set to IRecipe once
     ...     # IRecipe is defined.
     ...     favorite_recipe = Reference(schema=Interface)
@@ -43,30 +39,30 @@ All classes defined in this test are new-style classes.
 
     >>> class IComment(ITestDataObject):
     ...     target = Attribute('The object containing this comment.')
-    ...     text = TextLine(title=u"Text", required=True)
+    ...     text = TextLine(title="Text", required=True)
 
     >>> class ICookbook(ICommentTarget):
-    ...     name = TextLine(title=u"Name", required=True)
+    ...     name = TextLine(title="Name", required=True)
     ...     author = Reference(schema=IAuthor)
-    ...     cuisine = TextLine(title=u"Cuisine", required=False, default=None)
+    ...     cuisine = TextLine(title="Cuisine", required=False, default=None)
     ...     recipes = Attribute("List of recipes published in this cookbook.")
-    ...     cover = Bytes(0, 5000, title=u"An image of the cookbook's cover.")
+    ...     cover = Bytes(0, 5000, title="An image of the cookbook's cover.")
     ...     def removeRecipe(recipe):
     ...         """Remove a recipe from this cookbook."""
 
     >>> class IDish(ITestDataObject):
-    ...     name = TextLine(title=u"Name", required=True)
+    ...     name = TextLine(title="Name", required=True)
     ...     recipes = Attribute("List of recipes for this dish.")
     ...     def removeRecipe(recipe):
     ...         """Remove one of the recipes for this dish."""
 
     >>> class IRecipe(ICommentTarget):
-    ...     id = Int(title=u"Unique ID", required=True)
+    ...     id = Int(title="Unique ID", required=True)
     ...     dish = Reference(schema=IDish)
     ...     cookbook = Reference(schema=ICookbook)
-    ...     instructions = Text(title=u"How to prepare the recipe.",
+    ...     instructions = Text(title="How to prepare the recipe.",
     ...         required=True)
-    ...     private = Bool(title=u"Whether the public can see this recipe.",
+    ...     private = Bool(title="Whether the public can see this recipe.",
     ...                    default=False)
     ...     def delete():
     ...         """Delete this recipe."""
@@ -309,20 +305,20 @@ interface.
 
 Here are the "model objects" themselves:
 
-    >>> A1 = Author(u"Julia Child")
-    >>> A2 = Author(u"Irma S. Rombauer")
-    >>> A3 = Author(u"James Beard")
+    >>> A1 = Author("Julia Child")
+    >>> A2 = Author("Irma S. Rombauer")
+    >>> A3 = Author("James Beard")
     >>> AUTHORS = [A1, A2, A3]
 
-    >>> C1 = Cookbook(u"Mastering the Art of French Cooking", A1)
-    >>> C2 = Cookbook(u"The Joy of Cooking", A2)
-    >>> C3 = Cookbook(u"James Beard's American Cookery", A3)
+    >>> C1 = Cookbook("Mastering the Art of French Cooking", A1)
+    >>> C2 = Cookbook("The Joy of Cooking", A2)
+    >>> C3 = Cookbook("James Beard's American Cookery", A3)
     >>> COOKBOOKS = [C1, C2, C3]
 
     >>> D1 = Dish("Roast chicken")
-    >>> C1_D1 = Recipe(1, C1, D1, u"You can always judge...")
-    >>> C2_D1 = Recipe(2, C2, D1, u"Draw, singe, stuff, and truss...")
-    >>> C3_D1 = Recipe(3, C3, D1, u"A perfectly roasted chicken is...")
+    >>> C1_D1 = Recipe(1, C1, D1, "You can always judge...")
+    >>> C2_D1 = Recipe(2, C2, D1, "Draw, singe, stuff, and truss...")
+    >>> C3_D1 = Recipe(3, C3, D1, "A perfectly roasted chicken is...")
 
     >>> D2 = Dish("Baked beans")
     >>> C2_D2 = Recipe(4, C2, D2, "Preheat oven to...")
@@ -601,7 +597,7 @@ makes it possible to serve a link from a recipe to its cookbook.
     ...     "The part of a recipe that we expose through the web service."
     ...     cookbook = Reference(schema=ICookbook)
     ...     dish = Reference(schema=IDish)
-    ...     instructions = Text(title=u"Name", required=True)
+    ...     instructions = Text(title="Name", required=True)
     ...     comments = CollectionField(value_type=Reference(schema=IComment))
     ...     taggedValue(
     ...         LAZR_WEBSERVICE_NAME,
@@ -611,13 +607,13 @@ makes it possible to serve a link from a recipe to its cookbook.
 
     >>> from lazr.restful.fields import ReferenceChoice
     >>> class ICookbookEntry(IEntry):
-    ...     name = TextLine(title=u"Name", required=True)
-    ...     cuisine = TextLine(title=u"Cuisine", required=False, default=None)
+    ...     name = TextLine(title="Name", required=True)
+    ...     cuisine = TextLine(title="Cuisine", required=False, default=None)
     ...     author = ReferenceChoice(
     ...         schema=IAuthor, vocabulary=AuthorVocabulary())
     ...     recipes = CollectionField(value_type=Reference(schema=IRecipe))
     ...     comments = CollectionField(value_type=Reference(schema=IComment))
-    ...     cover = Bytes(0, 5000, title=u"An image of the cookbook's cover.")
+    ...     cover = Bytes(0, 5000, title="An image of the cookbook's cover.")
     ...     taggedValue(
     ...         LAZR_WEBSERVICE_NAME,
     ...         dict(
@@ -654,7 +650,7 @@ more on ``delegate_to()``.)
 
     >>> class FakeDict(dict):
     ...     def __init__(self, interface):
-    ...         super(FakeDict, self).__init__()
+    ...         super().__init__()
     ...         self.interface = interface
     ...     def __getitem__(self, key):
     ...         return self.interface
@@ -975,7 +971,7 @@ a named factory operation for creating a new cookbook.
     ...         TextLine(__name__='author_name'),
     ...         TextLine(__name__='title'),
     ...         TextLine(
-    ...             __name__='cuisine', default=u'Brazilian', required=False),
+    ...             __name__='cuisine', default='Brazilian', required=False),
     ...     )
     ...     return_type = Reference(schema=IRecipe)
     ...
@@ -1579,7 +1575,7 @@ results. In this case we do the same thing we do when serving a
 collection resource. We fetch one batch of results and represent it as
 a JSON hash containing a list of entries.
 
-    >>> class StubResultSet(object):
+    >>> class StubResultSet:
     ...     results = [C1_D1, C2_D1]
     ...
     ...     def __iter__(self):
@@ -1821,7 +1817,7 @@ server. The server will know that the client isn't actually trying to
 set the field value to 'tag:launchpad.net:2008:redacted'.
 
     >>> headers = {'CONTENT_TYPE' : 'application/json'}
-    >>> body = simplejson.dumps(author).encode('UTF-8')
+    >>> body = simplejson.dumps(author).encode()
     >>> put_request = create_web_service_request(
     ...     beard_url, body=body, environ=headers, method='PUT')
     >>> print(six.ensure_text(put_request.traverse(app)()))
@@ -1834,7 +1830,7 @@ PUT, even when its current value is redacted.
     >>> author['favorite_recipe_link'] = 'http://' + quote(
     ...     'api.cookbooks.dev/beta/cookbooks/'
     ...     'The Joy of Cooking/recipes/Roast chicken')
-    >>> body = simplejson.dumps(author).encode('UTF-8')
+    >>> body = simplejson.dumps(author).encode()
     >>> put_request = create_web_service_request(
     ...     beard_url, body=body, environ=headers, method='PUT')
     >>> print(six.ensure_text(put_request.traverse(app)()))
@@ -1854,7 +1850,7 @@ permission to see:
 
     >>> author['favorite_recipe_link'] = (
     ...     'http://api.cookbooks.dev' + private_recipe_url)
-    >>> body = simplejson.dumps(author).encode('UTF-8')
+    >>> body = simplejson.dumps(author).encode()
     >>> put_request = create_web_service_request(
     ...     beard_url, body=body, environ=headers, method='PUT')
     >>> print(put_request.traverse(app)())
@@ -2022,7 +2018,7 @@ server. Note also that another modification event is sent out and
 intercepted by the modified_cookbook() listener.
 
     >>> joy['name'] = 'The Joy of Cooking'
-    >>> body = simplejson.dumps(joy).encode('UTF-8')
+    >>> body = simplejson.dumps(joy).encode()
     >>> put_request = create_web_service_request(
     ...     '/beta/cookbooks/The%20Joy%20of%20Cooking%20%28revised%29',
     ...     body=body, environ=headers, method='PUT')
@@ -2061,12 +2057,12 @@ their URLs, we make the change by modifying the cookbook's
     ...     representation = {'author_link' : new_author_link}
     ...     resource = create_web_service_request(
     ...         '/beta/cookbooks/The%20Joy%20of%20Cooking',
-    ...         body=simplejson.dumps(representation).encode('UTF-8'),
+    ...         body=simplejson.dumps(representation).encode(),
     ...         environ=headers, method='PATCH', hostname=host).traverse(app)
     ...     return six.ensure_text(resource())
     >>> path = '/beta/authors/Julia%20Child'
 
-    >>> print(change_joy_author(u'http://api.cookbooks.dev' + path))
+    >>> print(change_joy_author('http://api.cookbooks.dev' + path))
     {...}
 
     >>> joy_resource = create_web_service_request(
@@ -2079,38 +2075,38 @@ When identifying an object by URL, make sure the hostname of your URL
 matches the hostname you're requesting. If they don't match, your
 request will fail.
 
-    >>> print(change_joy_author(u'http://not.the.same.host' + path))
+    >>> print(change_joy_author('http://not.the.same.host' + path))
     author_link: No such object...
 
 One possible source of hostname mismatches is the HTTP port. If the
 web service is served from a strange port, you'll need to specify that
 port in the URLs you send.
 
-    >>> print(change_joy_author(u'http://api.cookbooks.dev' + path,
+    >>> print(change_joy_author('http://api.cookbooks.dev' + path,
     ...                         host='api.cookbooks.dev:9000'))
     author_link: No such object...
 
-    >>> print(change_joy_author(u'http://api.cookbooks.dev:9000' + path,
+    >>> print(change_joy_author('http://api.cookbooks.dev:9000' + path,
     ...                         host='api.cookbooks.dev:9000'))
     {...}
 
 You don't have to specify the default port in the URLs you send, even
 if you specified it when you made the request.
 
-    >>> print(change_joy_author(u'http://api.cookbooks.dev' + path,
+    >>> print(change_joy_author('http://api.cookbooks.dev' + path,
     ...                         host='api.cookbooks.dev:80'))
     {...}
 
-    >>> print(change_joy_author(u'http://api.cookbooks.dev:80' + path,
+    >>> print(change_joy_author('http://api.cookbooks.dev:80' + path,
     ...                         host='api.cookbooks.dev'))
     {...}
 
-    >>> print(change_joy_author(u'https://api.cookbooks.dev' + path,
+    >>> print(change_joy_author('https://api.cookbooks.dev' + path,
     ...                         host='api.cookbooks.dev:443'))
     author_link: No such object...
 
     >>> webservice_configuration.use_https = True
-    >>> print(change_joy_author(u'https://api.cookbooks.dev' + path,
+    >>> print(change_joy_author('https://api.cookbooks.dev' + path,
     ...                         host='api.cookbooks.dev:443'))
     {...}
     >>> webservice_configuration.use_https = False
diff --git a/src/lazr/restful/example/base/tests/collection.txt b/src/lazr/restful/example/base/tests/collection.txt
index c2a47dc..e156a43 100644
--- a/src/lazr/restful/example/base/tests/collection.txt
+++ b/src/lazr/restful/example/base/tests/collection.txt
@@ -251,8 +251,8 @@ handling is in the validate() method of the 'search' field.
 The error message may contain Unicode characters:
 
     >>> from lazr.restful.testing.helpers import encode_response
-    >>> url = u"/cookbooks?ws.op=find_for_cuisine&cuisine=%E2%98%83"
-    >>> response = webservice.get(url.encode("utf-8"))
+    >>> url = b"/cookbooks?ws.op=find_for_cuisine&cuisine=%E2%98%83"
+    >>> response = webservice.get(url)
     >>> print(encode_response(response))
     HTTP/1.1 400 Bad Request
     ...
diff --git a/src/lazr/restful/example/base/tests/entry.txt b/src/lazr/restful/example/base/tests/entry.txt
index c260361..f24c7a3 100644
--- a/src/lazr/restful/example/base/tests/entry.txt
+++ b/src/lazr/restful/example/base/tests/entry.txt
@@ -870,46 +870,46 @@ the assertion. The string used in the assertion might not be a date.
 
 Or it might be a date that's not in UTC.
 
-    >>> print(patch_greens_copyright_date(u'2005-06-06T00:00:00.000000+05:00'))
+    >>> print(patch_greens_copyright_date('2005-06-06T00:00:00.000000+05:00'))
     HTTP/1.1 400 Bad Request
     ...
     copyright_date: Time not in UTC.
 
 There are five ways to specify UTC:
 
-    >>> print(patch_greens_copyright_date(u'2003-01-01T00:00:00.000000Z'))
+    >>> print(patch_greens_copyright_date('2003-01-01T00:00:00.000000Z'))
     HTTP/1.1 209 Content Returned
     ...
 
-    >>> print(patch_greens_copyright_date(u'2003-01-01T00:00:00.000000+00:00'))
+    >>> print(patch_greens_copyright_date('2003-01-01T00:00:00.000000+00:00'))
     HTTP/1.1 209 Content Returned
     ...
 
-    >>> print(patch_greens_copyright_date(u'2003-01-01T00:00:00.000000+0000'))
+    >>> print(patch_greens_copyright_date('2003-01-01T00:00:00.000000+0000'))
     HTTP/1.1 209 Content Returned
     ...
 
-    >>> print(patch_greens_copyright_date(u'2003-01-01T00:00:00.000000-00:00'))
+    >>> print(patch_greens_copyright_date('2003-01-01T00:00:00.000000-00:00'))
     HTTP/1.1 209 Content Returned
     ...
 
-    >>> print(patch_greens_copyright_date(u'2003-01-01T00:00:00.000000-0000'))
+    >>> print(patch_greens_copyright_date('2003-01-01T00:00:00.000000-0000'))
     HTTP/1.1 209 Content Returned
     ...
 
 A value with a missing timezone is treated as UTC.
 
-    >>> print(patch_greens_copyright_date(u'2003-01-01T00:00:00.000000'))
+    >>> print(patch_greens_copyright_date('2003-01-01T00:00:00.000000'))
     HTTP/1.1 209 Content Returned
     ...
 
 Less precise time measurements may also be acceptable.
 
-    >>> print(patch_greens_copyright_date(u'2003-01-01T00:00:00Z'))
+    >>> print(patch_greens_copyright_date('2003-01-01T00:00:00Z'))
     HTTP/1.1 209 Content Returned
     ...
 
-    >>> print(patch_greens_copyright_date(u'2003-01-01'))
+    >>> print(patch_greens_copyright_date('2003-01-01'))
     HTTP/1.1 209 Content Returned
     ...
 
@@ -942,7 +942,7 @@ An entry's read-only attributes can't be modified.
 
     >>> print(modify_cookbook(
     ...     'Everyday Greens',
-    ...     {'copyright_date' : u'2001-01-01T01:01:01+00:00Z'}, 'PATCH'))
+    ...     {'copyright_date' : '2001-01-01T01:01:01+00:00Z'}, 'PATCH'))
     HTTP/1.1 400 Bad Request
     ...
     copyright_date: You tried to modify a read-only attribute.
diff --git a/src/lazr/restful/example/base/tests/field.txt b/src/lazr/restful/example/base/tests/field.txt
index a1e51c7..0f6951f 100644
--- a/src/lazr/restful/example/base/tests/field.txt
+++ b/src/lazr/restful/example/base/tests/field.txt
@@ -410,7 +410,7 @@ a view on ICookbook called "description".
   ... def fake_renderer(context, field, request):
   ...     """Bold the original string, add a snowman, and encode UTF-8."""
   ...     def render(value):
-  ...         return (u"\N{SNOWMAN} <b>%s</b>" % value).encode("utf-8")
+  ...         return ("\N{SNOWMAN} <b>%s</b>" % value).encode()
   ...     return render
   >>> manager.registerAdapter(fake_renderer, name='description')
 
diff --git a/src/lazr/restful/marshallers.py b/src/lazr/restful/marshallers.py
index 20f6f9e..e8b38fe 100644
--- a/src/lazr/restful/marshallers.py
+++ b/src/lazr/restful/marshallers.py
@@ -314,7 +314,7 @@ class BytesFieldMarshaller(SimpleFieldMarshaller):
             value.seek(0)
             value = value.read()
         elif not isinstance(value, (bytes, str)):
-            value = str(value).encode("UTF-8")
+            value = str(value).encode()
         else:
             # Leave string conversion to _marshall_from_json_data.
             pass
@@ -326,7 +326,7 @@ class BytesFieldMarshaller(SimpleFieldMarshaller):
         Convert all strings to byte strings.
         """
         if isinstance(value, str):
-            value = value.encode("utf-8")
+            value = value.encode()
         return super()._marshall_from_json_data(value)
 
 
diff --git a/src/lazr/restful/simple.py b/src/lazr/restful/simple.py
index 3a2b271..fb85f40 100644
--- a/src/lazr/restful/simple.py
+++ b/src/lazr/restful/simple.py
@@ -396,7 +396,7 @@ class MultiplePathPartAbsoluteURL:
                 "Expected an iterable of strings for __path_parts__."
             )
 
-        escaped_parts = [quote(part.encode("utf-8"), _safe) for part in parts]
+        escaped_parts = [quote(part.encode(), _safe) for part in parts]
         return start_url + "/" + "/".join(escaped_parts)
 
     __call__ = __str__
diff --git a/src/lazr/restful/testing/webservice.py b/src/lazr/restful/testing/webservice.py
index 193ada8..97bbc11 100644
--- a/src/lazr/restful/testing/webservice.py
+++ b/src/lazr/restful/testing/webservice.py
@@ -398,16 +398,16 @@ class WebServiceCaller:
     def _writeHeaders(self, buf, headers):
         """Write MIME headers to a file object."""
         for key, value in headers:
-            buf.write(key.encode("UTF-8"))
+            buf.write(key.encode())
             buf.write(b": ")
-            buf.write(value.encode("UTF-8"))
+            buf.write(value.encode())
             buf.write(b"\r\n")
         buf.write(b"\r\n")
 
     def _writeBoundary(self, buf, boundary, closing=False):
         """Write a multipart boundary to a file object."""
         buf.write(b"--")
-        buf.write(boundary.encode("UTF-8"))
+        buf.write(boundary.encode())
         if closing:
             buf.write(b"--")
         buf.write(b"\r\n")
diff --git a/src/lazr/restful/tests/test_webservice.py b/src/lazr/restful/tests/test_webservice.py
index e8c8010..b762b2c 100644
--- a/src/lazr/restful/tests/test_webservice.py
+++ b/src/lazr/restful/tests/test_webservice.py
@@ -540,7 +540,7 @@ class HTMLRepresentationTest(EntryTestCase):
         super().setUp()
         self._register_url_adapter(IHasOneField)
         self.unicode_message = "Hello from a \N{SNOWMAN}"
-        self.utf8_message = self.unicode_message.encode("utf-8")
+        self.utf8_message = self.unicode_message.encode()
 
     def test_entry_html_representation_is_utf8(self):
         with self.entry_resource(