Comment 3 for bug 1839487

Right, so with 'debugLevel 3' in the configuration file, which isn't in there by default and was gleaned from the code, we are indeed getting some results, but not the desired ones.

As in, email sent by Google causes dkimpy-milter to crap out and throw tracebacks into syslog again. This is purely for incoming mail, in verify mode, no signing.

==
TypeError: a bytes-like object is required, not 'NoneType'
#012The above exception was the direct cause of the following exception:#012
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/Milter/__init__.py", line 772, in <lambda>#012
milter.set_eom_callback(lambda ctx: ctx.getpriv().eom())
File "/usr/local/lib/python3.7/dist-packages/dkimpy_milter/__init__.py", line 196, in eom#012 self.check_dkim(txt)
File "/usr/local/lib/python3.7/dist-packages/dkimpy_milter/__init__.py", line 292, in check_dkim#012 self.header_i = codecs.decode(d.signature_fields.get(b'i'), 'ascii')
TypeError: decoding with 'ascii' codec failed (TypeError: a bytes-like object is required, not 'NoneType')
==

Which results in Postfix throwing a transient error with '4.3.0 pymilter: untrapped exception in dkimpy-filter', and mail not being delivered.

That doesn't really say "ready for production", to me :-/