fix: Resolve mypy unused-ignore error for optional langchain import

- Add mypy override to disable warn_unused_ignores for langchain integration module
- Use placeholder class instead of None when langchain is not installed
- This allows the code to pass mypy both with and without langchain installed

The type: ignore comment is needed when langchain is NOT installed (CI),
but triggers unused-ignore when it IS installed (local dev). The mypy
override resolves this conflict.

Author: abrookins

agent-memory-client/agent_memory_client/integrations/langchain.py

@@ -46,12 +46,16 @@
     from agent_memory_client import MemoryAPIClient
 
 try:
-    from langchain_core.tools import StructuredTool
+    from langchain_core.tools import StructuredTool  # type: ignore  # noqa: F401
 
     LANGCHAIN_AVAILABLE = True
 except ImportError:
     LANGCHAIN_AVAILABLE = False
-    StructuredTool = None  # type: ignore[misc,assignment]
+
+    class StructuredTool:  # type: ignore[no-redef]
+        """Placeholder for when LangChain is not installed."""
+
+        pass
 
 
 def _check_langchain_available() -> None:

agent-memory-client/pyproject.toml

@@ -100,3 +100,7 @@ strict_equality = true
 [[tool.mypy.overrides]]
 module = "tests.*"
 disallow_untyped_defs = false
+
+[[tool.mypy.overrides]]
+module = "agent_memory_client.integrations.langchain"
+warn_unused_ignores = false