Fixed type warning

sigmaiq/llm/tools/query_to_sigma_rule.py

@@ -1,6 +1,6 @@
 import asyncio
 import json
-from typing import Union, Type
+from typing import Optional, Union, Type
 
 from langchain.prompts import ChatPromptTemplate
 from langchain.schema.language_model import BaseLanguageModel
@@ -50,10 +50,10 @@ class Config:
 
         extra = Extra.forbid
 
-    def _run(self, query: str = None, backend: str = None) -> str:
+    def _run(self, query: Optional[str] = None, backend: Optional[str] = None) -> str:
         return asyncio.run(self._arun(query, backend))
 
-    async def _arun(self, query: str = None, backend: str = None) -> str:
+    async def _arun(self, query: Optional[str] = None, backend: Optional[str] = None) -> str:
         template = """You are a cybersecurity detection engineering assistant bot specializing in Sigma Rule creation.
 You are assisting a user in taking a query for a security/SIEM product, and converting it to a Sigma Rule.
 The backend is used to validate the query and ensure it is compatible with the backend.