Import ABCs from collections.abc

Python 3 has moved all collection abstract base classes to
collections.abc. Python 3.7 started to deprecate the old aliases.

The whole import block needs to be protected with import-error and
no-name-in-module, because Python 2 doesn't have collections.abc module and
collections.abc.Mapping, while Python 3 doesn't have collections.Mapping.

Fixes: https://pagure.io/freeipa/issue/7609
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Fraser Tweedale <ftweedal@redhat.com>

ipatests/test_xmlrpc/xmlrpc_test.py

@@ -22,7 +22,6 @@ Base class for all XML-RPC tests
 """
 from __future__ import print_function
 
-import collections
 import datetime
 import inspect
 import unittest
@@ -34,6 +33,12 @@ from ipatests.util import assert_deepequal, Fuzzy
 from ipalib import api, request, errors
 from ipapython.version import API_VERSION
 
+# pylint: disable=no-name-in-module, import-error
+if six.PY3:
+    from collections.abc import Sequence
+else:
+    from collections import Sequence
+# pylint: enable=no-name-in-module, import-error
 
 # Matches a gidnumber like '1391016742'
 # FIXME: Does it make more sense to return gidnumber, uidnumber, etc. as `int`
@@ -57,7 +62,7 @@ fuzzy_base64 = Fuzzy('^[0-9A-Za-z/+]+={0,2}$')
 def fuzzy_sequence_of(fuzzy):
     """Construct a Fuzzy for a Sequence of values matching the given Fuzzy."""
     def test(xs):
-        if not isinstance(xs, collections.Sequence):
+        if not isinstance(xs, Sequence):
             return False
         else:
             return all(fuzzy == x for x in xs)