fix: correct type annotation

Overridden `supported_models` should be a `classmethod` rather than a `staticmethod`.

PiperOrigin-RevId: 790989895

src/google/adk/models/anthropic_llm.py

@@ -249,9 +249,9 @@ class Claude(BaseLlm):
   model: str = "claude-3-5-sonnet-v2@20241022"
   max_tokens: int = 8192
 
-  @staticmethod
+  @classmethod
   @override
-  def supported_models() -> list[str]:
+  def supported_models(cls) -> list[str]:
     return [r"claude-3-.*", r"claude-.*-4.*"]
 
   @override

src/google/adk/models/google_llm.py

@@ -75,9 +75,9 @@ class Gemini(BaseLlm):
   ```
   """
 
-  @staticmethod
+  @classmethod
   @override
-  def supported_models() -> list[str]:
+  def supported_models(cls) -> list[str]:
     """Provides the list of supported models.
 
     Returns:

src/google/adk/models/lite_llm.py

@@ -848,9 +848,9 @@ class LiteLlm(BaseLlm):
       response = await self.llm_client.acompletion(**completion_args)
       yield _model_response_to_generate_content_response(response)
 
-  @staticmethod
+  @classmethod
   @override
-  def supported_models() -> list[str]:
+  def supported_models(cls) -> list[str]:
     """Provides the list of supported models.
 
     LiteLlm supports all models supported by litellm. We do not keep track of

tests/unittests/testing_utils.py

@@ -282,8 +282,9 @@ class MockModel(BaseLlm):
 
       return cls(responses=responses)
 
-  @staticmethod
-  def supported_models() -> list[str]:
+  @classmethod
+  @override
+  def supported_models(cls) -> list[str]:
     return ['mock']
 
   def generate_content(