use PY2

Author: tomvanmele

src/compas/__init__.py

@@ -127,7 +127,7 @@
 
 
 __all__ = [
-    'WINDOWS', 'LINUX', 'OSX', 'MONO', 'IPY', 'RHINO', 'BLENDER',
+    'WINDOWS', 'LINUX', 'OSX', 'MONO', 'IPY', 'RHINO', 'BLENDER', 'PY2', 'PY3',
     'is_windows', 'is_linux', 'is_osx', 'is_mono', 'is_ironpython', 'is_rhino', 'is_blender',
     'set_precision',
     'get',

src/compas/datastructures/_mutablemapping.py

@@ -14,13 +14,10 @@
 from __future__ import print_function
 
 import compas
-
-__all__ = ['Mapping', 'MutableMapping']
-
-if compas.PY3:
-    import collections.abc as stdlib_collections
-else:
+if compas.PY2:
     import collections as stdlib_collections
+else:
+    import collections.abc as stdlib_collections
 
 
 class Mapping(object):

src/compas/datastructures/mesh/mesh.py

@@ -2,13 +2,16 @@
 from __future__ import division
 from __future__ import print_function
 
-import collections
-import sys
 from math import pi
 from itertools import product
 
 import compas
 
+if compas.PY2:
+    from collections import Mapping
+else:
+    from collections.abc import Mapping
+
 from compas.files import OBJ
 from compas.files import OFF
 from compas.files import PLY
@@ -454,19 +457,14 @@ def from_vertices_and_faces(cls, vertices, faces):
         """
         mesh = cls()
 
-        if sys.version_info[0] < 3:
-            mapping = collections.Mapping
-        else:
-            mapping = collections.abc.Mapping
-
-        if isinstance(vertices, mapping):
+        if isinstance(vertices, Mapping):
             for key, xyz in vertices.items():
                 mesh.add_vertex(key=key, attr_dict=dict(zip(('x', 'y', 'z'), xyz)))
         else:
             for x, y, z in iter(vertices):
                 mesh.add_vertex(x=x, y=y, z=z)
 
-        if isinstance(faces, mapping):
+        if isinstance(faces, Mapping):
             for fkey, vertices in faces.items():
                 mesh.add_face(vertices, fkey)
         else:

src/compas/datastructures/network/network.py

@@ -2,10 +2,13 @@
 from __future__ import absolute_import
 from __future__ import division
 
-import sys
-import collections
 import compas
 
+if compas.PY2:
+    from collections import Mapping
+else:
+    from collections.abc import Mapping
+
 from compas.files import OBJ
 
 from compas.utilities import geometric_key
@@ -192,12 +195,7 @@ def from_nodes_and_edges(cls, nodes, edges):
         """
         network = cls()
 
-        if sys.version_info[0] < 3:
-            mapping = collections.Mapping
-        else:
-            mapping = collections.abc.Mapping
-
-        if isinstance(nodes, mapping):
+        if isinstance(nodes, Mapping):
             for key, (x, y, z) in nodes.items():
                 network.add_node(key, x=x, y=y, z=z)
         else: