Code review comment for lp:~gtg-user/gtg/google-tasks-backend

For beginning couple of formal things:

1, get rid of print statements
2, have you written the backend from the beginning or you used
lp:~gtg-contributors/gtg/google_tasks for inspiration? In the later case you need to put credits into Author sections.
3, Your code have to satisfy PEP8 standard and PyFlakes check <use `make check` command>
4, Get rid of _bak.py file

I managed to get some traceback in console during update

Exception in thread Thread-10:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 552, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 760, in run
    self.function(*self.args, **self.kwargs)
  File "/home/izidor/projects/gtg/trunk/GTG/backends/genericbackend.py", line 653, in launch_setting_thread
    self.set_task(task)
  File "/home/izidor/projects/gtg/trunk/GTG/tools/interruptible.py", line 39, in new
    return fn(*args)
  File "/home/izidor/projects/gtg/trunk/GTG/backends/backend_gtasks.py", line 275, in set_task
    self._populate_gtask(task, gtask)
  File "/home/izidor/projects/gtg/trunk/GTG/backends/backend_gtasks.py", line 452, in _populate_gtask
    self.gtasks_proxy.update(gtask)
  File "/home/izidor/projects/gtg/trunk/GTG/backends/backend_gtasks.py", line 493, in update
    self.gtasks.task_update(gtask.get_tasklist(), gtask.get_id(), body)
  File "/home/izidor/projects/gtg/trunk/GTG/backends/gtasks/gtasks.py", line 169, in task_update
    return self.execute(self.get_service().tasks().update(tasklist=tasklist,task=task, body=body))
  File "/home/izidor/projects/gtg/trunk/GTG/backends/gtasks/gtasks.py", line 113, in execute
    return request.execute(http=self.http)
  File "/usr/local/lib/python2.7/dist-packages/google_api_python_client-1.0-py2.7.egg/oauth2client/util.py", line 120, in positional_wrapper
    return wrapped(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/google_api_python_client-1.0-py2.7.egg/apiclient/http.py", line 678, in execute
    raise HttpError(resp, content, uri=self.uri)
HttpError: <HttpError 400 when requesting https://www.googleapis.com/tasks/v1/lists/MTM0OTg2OTgwNTUxMDYzOTQ5MTU6MDow/tasks/MTM0OTg2OTgwNTUxMDYzOTQ5MTU6MDoxNzU4ODcwNTY1?alt=json returned "Invalid Value">

Wouldn't it be better to create a list for every tag and then copy tasks to each list?

Please, address those things so we can continue in reviewing your patch.