drop: py3.6- code

Author: ankostis

graphtik/network.py

@@ -82,19 +82,6 @@
 
 thread_pool: ContextVar[Pool] = ContextVar("thread_pool", default=Pool(7))
 
-if sys.version_info < (3, 6):
-    """
-    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/reference/classes/ordered.html#module-networkx.classes.ordered
-    """
-    from networkx import OrderedDiGraph as DiGraph
-
 
 class _DataNode(str):
     """

test/test_plot.py

@@ -161,13 +161,6 @@ def _check_plt_img(img):
 def test_plot_matpotlib(pipeline, tmp_path):
     ## Try matplotlib Window, but # without opening a Window.
 
-    if sys.version_info < (3, 5):
-        # On PY< 3.5 it fails with:
-        #   nose.proxy.TclError: no display name and no $DISPLAY environment variable
-        # eg https://travis-ci.org/ankostis/graphtik/jobs/593957996
-        import matplotlib
-
-        matplotlib.use("Agg")
     # do not open window in headless travis
     img = pipeline.plot(show=-1)
     _check_plt_img(img)