tools fix and formatting (#2441)

mem0/llms/openai.py

@@ -1,3 +1,4 @@
+import json
 import os
 import warnings
 from typing import Dict, List, Optional
@@ -34,7 +35,7 @@ class OpenAILLM(LLMBase):
                 warnings.warn(
                     "The environment variable 'OPENAI_API_BASE' is deprecated and will be removed in the 0.1.80. "
                     "Please use 'OPENAI_BASE_URL' instead.",
-                    DeprecationWarning
+                    DeprecationWarning,
                 )
 
             self.client = OpenAI(api_key=api_key, base_url=base_url)