Update llm_loader.py

llm_loader.py

@@ -1,10 +1,17 @@
 from langchain_openai import ChatOpenAI
+from tiktoken import encoding_for_model
+
+model = "gpt-4o-mini"
 
 def load_model(openai_api_key):
     return ChatOpenAI(
-        model_name="gpt-4o-mini",
+        model_name=model,
         openai_api_key=openai_api_key,
         temperature=0.01,
         max_tokens=4096,
         top_p=0.9
-    )
+    )
+
+def count_tokens(text, model=model):
+    encoder = encoding_for_model(model)
+    return len(encoder.encode(text))