DEP8 failure due to py3.10 incompatible import

[Andreas Hasenack]

In python 3.10, "from collections import <thing>" doesn't work anymore
and should be imported from collections.abc.

$ sh debian/tests/unittest

                                   [0/1942]
EE
======================================================================
ERROR: test_itemlist (unittest.loader._FailedTest)
----------------------------------------------------------------------
ImportError: Failed to import test module: test_itemlist
Traceback (most recent call last):
  File "/usr/lib/python3.10/unittest/loader.py", line 154, in loadTestsFromName
    module = __import__(module_name)
  File "/home/ubuntu/git/packages/python-orderedmultidict/python-orderedmultidict/tests/test_itemlist.py",
line 18, in <module>
    from orderedmultidict.itemlist import itemlist
  File "/home/ubuntu/git/packages/python-orderedmultidict/python-orderedmultidict/orderedmultidict/__init__.py",
line 14, in <module>
    from .orderedmultidict import * # noqa
  File "/home/ubuntu/git/packages/python-orderedmultidict/python-orderedmultidict/orderedmultidict/orderedmultidict.py",
line 15, in <module>
    from collections import MutableMapping
ImportError: cannot import name 'MutableMapping' from 'collections'
(/usr/lib/python3.10/collections/__init__.py)

======================================================================
ERROR: test_orderedmultidict (unittest.loader._FailedTest)
----------------------------------------------------------------------
ImportError: Failed to import test module: test_orderedmultidict
Traceback (most recent call last):
  File "/usr/lib/python3.10/unittest/loader.py", line 154, in loadTestsFromName
    module = __import__(module_name)
  File "/home/ubuntu/git/packages/python-orderedmultidict/python-orderedmultidict/tests/test_orderedmultidict.py",
line 20, in <module>
    from orderedmultidict.orderedmultidict import omdict
  File "/home/ubuntu/git/packages/python-orderedmultidict/python-orderedmultidict/orderedmultidict/__init__.py",
line 14, in <module>
    from .orderedmultidict import * # noqa
  File "/home/ubuntu/git/packages/python-orderedmultidict/python-orderedmultidict/orderedmultidict/orderedmultidict.py",
line 15, in <module>
    from collections import MutableMapping
ImportError: cannot import name 'MutableMapping' from 'collections'
(/usr/lib/python3.10/collections/__init__.py)

----------------------------------------------------------------------
Ran 2 tests in 0.000s

Upstream fixed it in
https://github.com/gruns/orderedmultidict/commit/154e2c52a0368715c22e856f0c135e9770365d4d
which is part of the 1.0.1 release:

[Launchpad Janitor (janitor)]

This bug was fixed in the package python-orderedmultidict - 1.0-4ubuntu1

---------------
python-orderedmultidict (1.0-4ubuntu1) jammy; urgency=medium

  * d/p/py310-fix-collections-import.patch: fix collections import
    for python 3.10+ (LP: #1959929)

 -- Andreas Hasenack <email address hidden> Thu, 03 Feb 2022 18:59:08 +0000