add (overwrite with) mypy stubs, if available

stdlib/3/inspect.pyi

@@ -0,0 +1,31 @@
+# Stubs for inspect
+
+from typing import Any, Tuple, List, Callable
+
+_object = object
+
+def getmembers(obj: object, predicate: Callable[[Any], bool]) -> List[Tuple[str, object]]: ...
+
+def isclass(obj: object) -> bool: ...
+
+# namedtuple('Attribute', 'name kind defining_class object')
+class Attribute(tuple):
+    name = ...  # type: str
+    kind = ...  # type: str
+    defining_class = ...  # type: type
+    object = ...  # type: _object
+
+def classify_class_attrs(cls: type) -> List[Attribute]: ...
+
+def cleandoc(doc: str) -> str: ...
+
+def getsourcelines(obj: object) -> Tuple[List[str], int]: ...
+
+# namedtuple('ArgSpec', 'args varargs keywords defaults')
+class ArgSpec(tuple):
+    args = ...  # type: List[str]
+    varargs = ...  # type: str
+    keywords = ...  # type: str
+    defaults = ...  # type: tuple
+
+def getargspec(func: object) -> ArgSpec: ...