chore: Fix linting in Anthropic (#2251)

* Fix linting

* Remove unused import

Author: sjrl

integrations/anthropic/tests/test_chat_generator.py

@@ -1171,7 +1171,7 @@ def test_convert_message_to_anthropic_format_with_image(self):
         image_content = ImageContent(base64_image=base64_image, mime_type="image/png")
         message = ChatMessage.from_user(content_parts=["What's in this image?", image_content])
 
-        system_messages, non_system_messages = _convert_messages_to_anthropic_format([message])
+        _, non_system_messages = _convert_messages_to_anthropic_format([message])
 
         assert len(non_system_messages) == 1
         anthropic_message = non_system_messages[0]

integrations/anthropic/tests/test_generator.py

@@ -20,7 +20,7 @@ def test_init_default(self, monkeypatch):
 
     def test_init_fail_wo_api_key(self, monkeypatch):
         monkeypatch.delenv("ANTHROPIC_API_KEY", raising=False)
-        with pytest.raises(ValueError, match="None of the .* environment variables are set"):
+        with pytest.raises(ValueError, match=r"None of the .* environment variables are set"):
             AnthropicGenerator()
 
     def test_init_with_parameters(self):
@@ -113,7 +113,7 @@ def test_from_dict_fail_wo_env_var(self, monkeypatch):
                 "max_retries": None,
             },
         }
-        with pytest.raises(ValueError, match="None of the .* environment variables are set"):
+        with pytest.raises(ValueError, match=r"None of the .* environment variables are set"):
             AnthropicGenerator.from_dict(data)
 
     def test_run(self, mock_chat_completion):