FIX(<PY3.5): ORDERED DiGRAPH for old Python to fix TCs

Author: ankostis

graphkit/network.py

@@ -65,6 +65,7 @@
 """
 import logging
 import os
+import sys
 import time
 from collections import defaultdict, namedtuple
 from io import StringIO
@@ -79,6 +80,31 @@
 
 log = logging.getLogger(__name__)
 
+
+if sys.version_info < (3, 6):
+    from collections import OrderedDict
+    from .digraph import DiGraph
+
+    class OrderedDiGraph(DiGraph):
+        """
+        Consistently ordered variant of :class:`~networkx.DiGraph`.
+        
+        PY3.6 has inmsertion-order dicts, but PY3.5 has not.
+        And behvavior *and TCs) in these environments may fail spuriously!
+        Still *subgraphs* may not patch!
+
+        Fix from: 
+        https://networkx.github.io/documentation/latest/_modules/networkx/classes/ordered.html
+        """
+        node_dict_factory = OrderedDict
+        adjlist_outer_dict_factory = OrderedDict
+        adjlist_inner_dict_factory = OrderedDict
+        edge_attr_dict_factory = OrderedDict
+
+    # monkeypatch
+    nx.DiGraph = OrderedDiGraph
+
+
 class DataPlaceholderNode(str):
     """
     Dag node naming a data-value produced or required by an operation.