add (overwrite with) mypy stubs, if available

stdlib/2.7/hashlib.pyi

@@ -0,0 +1,27 @@
+# Stubs for hashlib (Python 2)
+
+from typing import Tuple
+
+class _hash(object):
+    # This is not actually in the module namespace.
+    digest_size = 0
+    block_size = 0
+    def update(self, arg: str) -> None: ...
+    def digest(self) -> str: ...
+    def hexdigest(self) -> str: ...
+    def copy(self) -> _hash: ...
+
+def new(algo: str = None) -> _hash: ...
+
+def md5(s: str = None) -> _hash: ...
+def sha1(s: str = None) -> _hash: ...
+def sha224(s: str = None) -> _hash: ...
+def sha256(s: str = None) -> _hash: ...
+def sha384(s: str = None) -> _hash: ...
+def sha512(s: str = None) -> _hash: ...
+
+algorithms = ...  # type: Tuple[str, ...]
+algorithms_guaranteed = ...  # type: Tuple[str, ...]
+algorithms_available = ...  # type: Tuple[str, ...]
+
+def pbkdf2_hmac(name: str, password: str, salt: str, rounds: int, dklen: int = None) -> str: ...