Compatibility with networkx 2.5

[thatch]

Fixes #1644

Description of proposed changes

networkx 2.5 has been out for a while now, and some deprecated apis were removed in 2.4 or so. This code should be compatible with any version in the 2.2-2.5 range, although there is a test failure near the "Singleton clique" comments.

Related issue(s)

Fixes #1644

Test plan

Ran the unittests. tox -e py37. One failure, noted above, which I could use help understanding.

Checklist

Need help on these? Just ask!

• I have read the CONTRIBUTING document.
• [n/a] I have updated the documentation accordingly.
• [n/a] I have added tests to cover my changes.
• [n/a] I have run tox -e complex and/or tox -e spark if appropriate.
• All new and existing tests passed.

[brahmaneya]

Hi @thatch ,

The test is failing because nx.chordal_graph_cliques is now returning the singleton cliques in a different order. You can fix the test by replacing lines 200-208 in snorkel/test/labeling/model/test_label_model.py with

        for j in range(m):
            node = lm.c_tree.nodes[i]
            self.assertEqual(len(node['members']), 1)
            if 1 in node['members']:
                self.assertEqual(L_aug[0, node["start_index"]], 1)
            if 2 in node['members']:
                self.assertEqual(L_aug[0, 1 + node["start_index"]], 0)

[codecov]

Codecov Report

Merging #1645 (a33011c) into master (b3b0669) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1645   +/-   ##
=======================================
  Coverage   97.31%   97.31%           
=======================================
  Files          68       68           
  Lines        2157     2157           
  Branches      348      348           
=======================================
  Hits         2099     2099           
  Misses         30       30           
  Partials       28       28           

Impacted Files	Coverage Δ
snorkel/labeling/model/graph_utils.py	100.00% <100.00%> (ø)
snorkel/labeling/model/label_model.py	96.30% <100.00%> (ø)

[thatch]

Tests pass now, @brahmaneya