Attempt to satisfy RTD by using sphinxcontrib.napoleon.

docs/conf.py

@@ -16,6 +16,8 @@ import sys
 import os
 import re
 
+on_rtd = os.getenv('READTHEDOCS') == 'True'
+
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
@@ -32,9 +34,13 @@ sys.path.insert(0, os.path.abspath('..'))
 extensions = [
     'sphinx.ext.autodoc',
     'sphinx.ext.extlinks',
-    'sphinx.ext.napoleon',
 ]
 
+if on_rtd:
+  extensions.append('sphinxcontrib.napoleon')
+else:
+  extensions.append('sphinx.ext.napoleon')
+
 autodoc_member_order = 'bysource'
 
 extlinks = {
@@ -153,7 +159,7 @@ html_theme = 'sphinx_rtd_theme'
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static']
+# html_static_path = ['_static']
 
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied