add doc string to vertex llm base

litellm/llms/vertex_ai_and_google_ai_studio/vertex_llm_base.py

@@ -1,3 +1,9 @@
+"""
+Base Vertex, Google AI Studio LLM Class
+
+Handles Authentication and generating request urls for Vertex AI and Google AI Studio
+"""
+
 import json
 import os
 from typing import TYPE_CHECKING, Any, Dict, Literal, Optional, Tuple