Attempt to resolve autodoc build error

docs/source/conf.py

@@ -43,7 +43,6 @@ release = '0.1.0-alpha.0'
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = [
-    'recommonmark',
     'sphinx.ext.autodoc',
     'sphinx.ext.doctest',
     'sphinx.ext.intersphinx',
@@ -60,6 +59,12 @@ templates_path = ['.templates']
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
 #
+
+source_parsers = {
+    '.md': CommonMarkParser,
+}
+
+
 source_suffix = ['.rst', '.md', '.txt']
 
 # The master toctree document.
@@ -196,12 +201,9 @@ def remove_module_docstring(app, what, name, obj, options, lines):
         del lines[:]
 
 
-# If true, `todo` and `todoList` produce output, else they produce nothing.
 todo_include_todos = False
 
-
 def setup(app):
-    github_doc_root = 'https://github.com/nucypher/nucypher/tree/master/docs'
     local_source_root = './'
 
     app.add_config_value('recommonmark_config', {

nucypher/characters/base.py

@@ -317,8 +317,7 @@ class Character(Learner):
         :param signature: The signature to check.
         :param decrypt: Whether or not to decrypt the messages.
 
-        :return: Whether or not the signature is valid, the decrypted plaintext
-            or NO_DECRYPTION_PERFORMED
+        :return: Whether or not the signature is valid, the decrypted plaintext or NO_DECRYPTION_PERFORMED
         """
         sender_pubkey_sig = stranger.stamp.as_umbral_pubkey()
         with suppress(AttributeError):
@@ -386,7 +385,7 @@ class Character(Learner):
     def sign(self, message):
         return self._crypto_power.power_ups(SigningPower).sign(message)
 
-    def public_keys(self, power_up_class: ClassVar) -> Union[Tuple, UmbralPublicKey]:
+    def public_keys(self, power_up_class: ClassVar):
         """
         Pass a power_up_class, get the public material for this Character which corresponds to that
         class - whatever type of object that may be.

nucypher/crypto/powers.py

@@ -187,7 +187,7 @@ class KeyPairBasedPower(CryptoPowerUp):
         else:
             raise PowerUpError("This {} doesn't provide {}.".format(self.__class__, item))
 
-    def public_key(self):
+    def public_key(self) -> 'UmbralPublicKey':
         return self.keypair.pubkey