Fix type-checker errors and linting issues

Co-Authored-By: Joe Moura <joao@crewai.com>

src/crewai/llm.py

@@ -230,7 +230,10 @@ class LLM:
 
     def supports_function_calling(self) -> bool:
         try:
-            params = get_supported_openai_params(model=self.model)
+            # Handle None model case
+            if self.model is None:
+                return False
+            params = get_supported_openai_params(model=str(self.model))
             return "response_format" in params
         except Exception as e:
             logging.error(f"Failed to get supported params: {str(e)}")
@@ -238,7 +241,10 @@ class LLM:
 
     def supports_stop_words(self) -> bool:
         try:
-            params = get_supported_openai_params(model=self.model)
+            # Handle None model case
+            if self.model is None:
+                return False
+            params = get_supported_openai_params(model=str(self.model))
             return "stop" in params
         except Exception as e:
             logging.error(f"Failed to get supported params: {str(e)}")

tests/unit/test_llm.py

@@ -1,6 +1,7 @@
-from crewai.llm import LLM
 import pytest
 
+from crewai.llm import LLM
+
 
 @pytest.mark.parametrize(
     "invalid_model,error_message",