Drop use of deprecated collections classes

Many classes have moved from collections to collections.abc. The
original imports work, but emit deprecation warnings.

Now that we are py3-only, we can drop any references to the older
deprecated locations.

Change-Id: I24b13c8654a33d99bf687a44a36cfdace39e3866
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

3 files changed, 8 insertions, 15 deletions

diff --git a/taskflow/atom.py b/taskflow/atom.py
index f356247..6e41204 100644
--- a/taskflow/atom.py
+++ b/taskflow/atom.py
@@ -17,6 +17,7 @@
 
 import abc
 import collections
+from collections import abc as cabc
 import itertools
 
 from oslo_utils import reflection
@@ -28,8 +29,8 @@ from taskflow.utils import misc
 
 
 # Helper types tuples...
-_sequence_types = (list, tuple, collections.Sequence)
-_set_types = (set, collections.Set)
+_sequence_types = (list, tuple, cabc.Sequence)
+_set_types = (set, cabc.Set)
 
 # the default list of revert arguments to ignore when deriving
 # revert argument mapping from the revert method signature
diff --git a/taskflow/types/sets.py b/taskflow/types/sets.py
index 95da1d9..bbd988d 100644
--- a/taskflow/types/sets.py
+++ b/taskflow/types/sets.py
@@ -15,16 +15,8 @@
 #    under the License.
 
 import collections
-
-# TODO(smcginnis) update this once six has support for collections.abc
-# (https://github.com/benjaminp/six/pull/241) or clean up once we drop py2.7.
-try:
-    from collections.abc import Hashable
-    from collections.abc import Set
-except ImportError:
-    from collections import Hashable
-    from collections import Set
-
+from collections.abc import Hashable
+from collections.abc import Set
 import itertools
 
 import six
diff --git a/taskflow/utils/iter_utils.py b/taskflow/utils/iter_utils.py
index d35fe16..8591d23 100644
--- a/taskflow/utils/iter_utils.py
+++ b/taskflow/utils/iter_utils.py
@@ -14,7 +14,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import collections
+from collections import abc
 import itertools
 
 import six
@@ -25,7 +25,7 @@ def _ensure_iterable(func):
 
     @six.wraps(func)
     def wrapper(it, *args, **kwargs):
-        if not isinstance(it, collections.Iterable):
+        if not isinstance(it, abc.Iterable):
             raise ValueError("Iterable expected, but '%s' is not"
                              " iterable" % it)
         return func(it, *args, **kwargs)
@@ -109,7 +109,7 @@ def unique_seen(its, seen_selector=None):
 
     all_its = list(its)
     for it in all_its:
-        if not isinstance(it, collections.Iterable):
+        if not isinstance(it, abc.Iterable):
             raise ValueError("Iterable expected, but '%s' is"
                              " not iterable" % it)
     return _gen_it(all_its)