fix(mypy): use separate variable for processed contents to satisfy type checker

Reassigning contents (typed as ContentListUnion) with list[Content]
caused mypy errors. Use processed_contents as a separate variable instead.

Author: Adewale-1

google/genai/models.py

@@ -4707,10 +4707,10 @@ def _generate_content(
       contents: Union[types.ContentListUnion, types.ContentListUnionDict],
       config: Optional[types.GenerateContentConfigOrDict] = None,
   ) -> types.GenerateContentResponse:
-    contents = _process_contents_for_generation(self._api_client, contents)
+    processed_contents = _process_contents_for_generation(self._api_client, contents)
     parameter_model = types._GenerateContentParameters(
         model=model,
-        contents=contents,
+        contents=processed_contents,
         config=config,
     )
 
@@ -4789,10 +4789,10 @@ def _generate_content_stream(
       contents: Union[types.ContentListUnion, types.ContentListUnionDict],
       config: Optional[types.GenerateContentConfigOrDict] = None,
   ) -> Iterator[types.GenerateContentResponse]:
-    contents = _process_contents_for_generation(self._api_client, contents)
+    processed_contents = _process_contents_for_generation(self._api_client, contents)
     parameter_model = types._GenerateContentParameters(
         model=model,
-        contents=contents,
+        contents=processed_contents,
         config=config,
     )
 
@@ -6668,10 +6668,10 @@ async def _generate_content(
       contents: Union[types.ContentListUnion, types.ContentListUnionDict],
       config: Optional[types.GenerateContentConfigOrDict] = None,
   ) -> types.GenerateContentResponse:
-    contents = _process_contents_for_generation(self._api_client, contents)
+    processed_contents = _process_contents_for_generation(self._api_client, contents)
     parameter_model = types._GenerateContentParameters(
         model=model,
-        contents=contents,
+        contents=processed_contents,
         config=config,
     )
 
@@ -6750,10 +6750,10 @@ async def _generate_content_stream(
       contents: Union[types.ContentListUnion, types.ContentListUnionDict],
       config: Optional[types.GenerateContentConfigOrDict] = None,
   ) -> Awaitable[AsyncIterator[types.GenerateContentResponse]]:
-    contents = _process_contents_for_generation(self._api_client, contents)
+    processed_contents = _process_contents_for_generation(self._api_client, contents)
     parameter_model = types._GenerateContentParameters(
         model=model,
-        contents=contents,
+        contents=processed_contents,
         config=config,
     )