Merge pull request #110 from PerchunPak/patch-1

Fix type checking error while passing a lambda to `inject.configure`

Author: ivankorobkov

src/inject/__init__.py

@@ -113,7 +113,7 @@ def my_config(binder):
 Binding = Union[Type[Injectable], Hashable]
 Constructor = Callable[[], Injectable]
 Provider = Constructor
-BinderCallable = Callable[['Binder'], None]
+BinderCallable = Callable[['Binder'], Optional['Binder']]
 
 
 class ConstructorTypeError(TypeError):