Chore: Simplify the type-signature for contents.

This is a superset of what was here before, it shouldn't break anyone.
- It removes the redundant list types (`list[x|y] | list[x|y|z]`).
- It adds the missing `PartDict` and `FileDict` entries so `generate_content(contents={'text': "hello?"})` will pass mypy now.
- Adds tests for `contents:File` and `contents:FileDict`
- Reduces total formatted lines from 51 -> 42
- Reduces nesting "[" from 11 to 7.
- Reorders to put simple types first.

PiperOrigin-RevId: 789105998

Author: MarkDaoust

google/genai/models.py

@@ -5746,7 +5746,7 @@ def generate_content(
       self,
       *,
       model: str,
-      contents: Union[types.ContentListUnion, types.ContentListUnionDict],
+      contents: types.ContentListUnionDict,
       config: Optional[types.GenerateContentConfigOrDict] = None,
   ) -> types.GenerateContentResponse:
     """Makes an API request to generate content using a model.
@@ -5882,7 +5882,7 @@ def generate_content_stream(
       self,
       *,
       model: str,
-      contents: Union[types.ContentListUnion, types.ContentListUnionDict],
+      contents: types.ContentListUnionDict,
       config: Optional[types.GenerateContentConfigOrDict] = None,
   ) -> Iterator[types.GenerateContentResponse]:
     """Makes an API request to generate content using a model and yields the model's response in chunks.

google/genai/tests/data/story.txt

@@ -0,0 +1,7 @@
+The old lighthouse keeper, Silas, squinted at the churning sea. A storm, the likes of which he hadn't seen in fifty years, was brewing. Waves, the size of houses, were crashing against the jagged rocks below. The wind howled like a banshee, and the rain stung his face like a thousand tiny needles.
+
+He checked the lamp, its beam a comforting, steady light against the growing darkness. It was his duty, his oath, to keep that light burning, no matter what. He'd seen too many ships lost to the treacherous coast.
+
+Suddenly, a monstrous wave slammed into the lighthouse, shaking it to its foundations. The lamp flickered, and a cold dread washed over Silas. He scrambled to re-ignite the flame, his hands trembling. He had to, for the sake of the ships, and for the memory of all the sailors he had saved. He managed to get it back on just as the next huge wave hit.
+
+The storm raged for what felt like an eternity. When the first rays of dawn finally broke through the clouds, the sea had calmed, and a small ship, battered but intact, was sailing towards the harbor. Silas, exhausted but relieved, watched the ship safely reach the shore. He knew that his light had guided them through the sh**storm. He smiled, the light reflecting in his kind eyes, and went to make his morning coffee.

google/genai/tests/models/test_generate_content_part.py

@@ -486,18 +486,66 @@ def test_model_content_text(client):
     assert response.text
 
 
+def test_from_file_input(client):
+  with pytest_helper.exception_if_vertex(client, ValueError):
+    file = client.files.upload(file='tests/data/story.txt')
+    client.models.generate_content(
+        model='gemini-2.5-flash',
+        contents=file,
+    )
+    client.models.generate_content(
+        model='gemini-2.5-flash',
+        contents=[
+            'Summarize this file',
+            file,
+        ],
+    )
+    client.models.generate_content(
+        model='gemini-2.5-flash',
+        contents=[['Summarize this file', file]],
+    )
+
+
+def test_from_file_dict_input(client):
+  with pytest_helper.exception_if_vertex(client, ValueError):
+    file = client.files.upload(file='tests/data/story.txt')
+    file_dict = file.model_dump()
+    client.models.generate_content(
+        model='gemini-2.5-flash',
+        contents=file_dict,
+    )
+    client.models.generate_content(
+        model='gemini-2.5-flash',
+        contents=[
+            'Summarize this file',
+            file_dict,
+        ],
+    )
+    client.models.generate_content(
+        model='gemini-2.5-flash',
+        contents=[['Summarize this file', file_dict]],
+    )
+
+
 def test_from_uploaded_file_uri(client):
-  with pytest_helper.exception_if_vertex(client, errors.ClientError):
+  with pytest_helper.exception_if_vertex(client, ValueError):
+    file = client.files.upload(file='tests/data/story.txt')
+    file_part = types.Part.from_uri(file_uri=file.uri, mime_type='text/plain')
     client.models.generate_content(
-        model='gemini-1.5-flash',
+        model='gemini-2.5-flash',
+        contents=file_part,
+    )
+    client.models.generate_content(
+        model='gemini-2.5-flash',
         contents=[
             'Summarize this file',
-            types.Part.from_uri(
-                file_uri='https://generativelanguage.googleapis.com/v1beta/files/w1l20sq33nwn',
-                mime_type='text/plain',
-            ),
+            file_part,
         ],
     )
+    client.models.generate_content(
+        model='gemini-2.5-flash',
+        contents=[['Summarize this file', file_part]],
+    )
 
 
 def test_from_uri_inferred_mime_type(client):

google/genai/types.py

@@ -3676,19 +3676,25 @@ class FileDict(TypedDict, total=False):
 
 FileOrDict = Union[File, FileDict]
 
+
 if _is_pillow_image_imported:
-  PartUnion = Union[File, Part, PIL_Image, str]
+  PartUnion = Union[str, PIL_Image, File, Part]
 else:
-  PartUnion = Union[File, Part, str]  # type: ignore[misc]
+  PartUnion = Union[str, File, Part]  # type: ignore[misc]
 
 
-PartUnionDict = Union[PartUnion, PartDict]
+if _is_pillow_image_imported:
+  PartUnionDict = Union[str, PIL_Image, File, FileDict, Part, PartDict]
+else:
+  PartUnionDict = Union[str, File, FileDict, Part, PartDict]  # type: ignore[misc]
 
 
-ContentUnion = Union[Content, list[PartUnion], PartUnion]
+ContentUnion = Union[Content, PartUnion, list[PartUnion]]
 
 
-ContentUnionDict = Union[ContentUnion, ContentDict]
+ContentUnionDict = Union[
+    Content, ContentDict, PartUnionDict, list[PartUnionDict]
+]
 
 
 class GenerationConfigRoutingConfigAutoRoutingMode(_common.BaseModel):
@@ -3764,10 +3770,10 @@ class GenerationConfigRoutingConfigDict(TypedDict, total=False):
 ]
 
 
-SpeechConfigUnion = Union[SpeechConfig, str]
+SpeechConfigUnion = Union[str, SpeechConfig]
 
 
-SpeechConfigUnionDict = Union[SpeechConfigUnion, SpeechConfigDict]
+SpeechConfigUnionDict = Union[str, SpeechConfig, SpeechConfigDict]
 
 
 class GenerateContentConfig(_common.BaseModel):
@@ -4160,10 +4166,10 @@ class GenerateContentConfigDict(TypedDict, total=False):
 ]
 
 
-ContentListUnion = Union[list[ContentUnion], ContentUnion]
+ContentListUnion = Union[ContentUnion, list[ContentUnion]]
 
 
-ContentListUnionDict = Union[list[ContentUnionDict], ContentUnionDict]
+ContentListUnionDict = Union[ContentUnionDict, list[ContentUnionDict]]
 
 
 class _GenerateContentParameters(_common.BaseModel):
@@ -12594,13 +12600,17 @@ class LiveClientRealtimeInputDict(TypedDict, total=False):
     LiveClientRealtimeInput, LiveClientRealtimeInputDict
 ]
 
+
 if _is_pillow_image_imported:
-  BlobImageUnion = Union[Blob, PIL_Image]
+  BlobImageUnion = Union[PIL_Image, Blob]
 else:
   BlobImageUnion = Blob  # type: ignore[misc]
 
 
-BlobImageUnionDict = Union[BlobImageUnion, BlobDict]
+if _is_pillow_image_imported:
+  BlobImageUnionDict = Union[PIL_Image, Blob, BlobDict]
+else:
+  BlobImageUnionDict = Union[Blob, BlobDict]  # type: ignore[misc]
 
 
 class LiveSendRealtimeInputParameters(_common.BaseModel):