added type hint for the diff.

changelogs/fragments/0.1.1.yml

@@ -1,3 +1,4 @@
 ---
 minor_changes:
   - Added an type hint to the update_doc function
+  - Added Type hint to the dictionary argument of the diff method

plugins/module_utils/module.py

@@ -1,6 +1,6 @@
 import pathlib
 from copy import deepcopy
-from typing import Any, Callable, ClassVar, Dict, NoReturn, Optional, Type, TypeVar, Union, overload
+from typing import Any, Callable, ClassVar, Dict, NoReturn, Optional, Type, TypeVar, Union, overload, TypedDict
 from ansible.utils.display import Display
 
 import ansible.module_utils.basic as basic
@@ -18,6 +18,13 @@ __all__ = (
 T = TypeVar("T")
 
 
+class TypedDiff(TypedDict):
+    before: str
+    after: str
+    before_header: Optional[str] = None
+    after_header: Optional[str] = None
+
+
 def docify(input: Union[dict, AnsibleParameter]) -> dict:
     options = dict()
     for name, help in input.items():
@@ -82,7 +89,7 @@ class AnsibleModule(object):
         self.result[key] = value
 
     @overload
-    def diff(self, diff: Dict[str, str]):  # pragma: nocover
+    def diff(self, diff: TypedDiff):  # pragma: nocover
         pass
 
     @overload