Some type hint and docstring fixes

docs/source/using_pyumbral.rst

@@ -56,7 +56,7 @@ A delegating key pair and a signing key pair.
 Encrypt with a public key
 --------------------------
 Now let's encrypt data with Alice's public key.
-Invocation of :py:func:`encrypt` returns both a ``capsule`` and a ``ciphertext``.
+Invocation of :py:func:`umbral.encrypt` returns both a ``capsule`` and a ``ciphertext``.
 Note that anyone with Alice's public key can perform this operation.
 
 

umbral/serializable.py

@@ -22,10 +22,10 @@ class Deserializable(HasSerializedSize):
     A mixin for composable deserialization.
     """
 
-    _T = TypeVar('_T', bound='Deserializable')
+    Self = TypeVar('Self', bound='Deserializable')
 
     @classmethod
-    def from_bytes(cls: Type[_T], data: bytes) -> _T:
+    def from_bytes(cls: Type[Self], data: bytes) -> Self:
         """
         Restores the object from serialized bytes.
         """
@@ -64,7 +64,7 @@ class Deserializable(HasSerializedSize):
 
     @classmethod
     @abstractmethod
-    def _from_exact_bytes(cls: Type[_T], data: bytes) -> _T:
+    def _from_exact_bytes(cls: Type[Self], data: bytes) -> Self:
         """
         Deserializes the object from a bytestring of exactly the expected length
         (defined by ``serialized_size()``).

umbral/signing.py

@@ -22,7 +22,7 @@ class Signer:
     def __init__(self, secret_key: SecretKey):
         self.__secret_key = secret_key
 
-    def sign_digest(self, digest: 'Hash') -> 'Signature':
+    def sign_digest(self, digest: Hash) -> 'Signature':
 
         secret_bn = self.__secret_key.secret_scalar()._backend_bignum
         r_int, s_int = openssl.ecdsa_sign(curve=CURVE,
@@ -75,7 +75,7 @@ class Signature(Serializable, Deserializable):
         self.r = r
         self.s = s
 
-    def verify_digest(self, verifying_key: 'PublicKey', digest: 'Hash') -> bool:
+    def verify_digest(self, verifying_key: PublicKey, digest: Hash) -> bool:
         return openssl.ecdsa_verify(curve=CURVE,
                                     sig_r=int(self.r),
                                     sig_s=int(self.s),