Refactor respond function to use consistent parameter naming and improve clarity

app.py

@@ -1,13 +1,13 @@
 import gradio as gr
-from langchain_core.messages import HumanMessage
 from langchain.chat_models import init_chat_model
+from langchain_core.messages import HumanMessage
 
 model = init_chat_model("gemini-2.0-flash", model_provider="google_genai")
 
 
 def respond(
     user_input: str,
-    messages: list[dict],
+    dialog_history: list[dict],
     system_message: str,
     max_new_tokens: int,
     temperature: float,
@@ -17,10 +17,11 @@ def respond(
     Respond to user input using the model.
     """
     response = model.invoke(
-        messages + [HumanMessage(content=user_input)],
+        dialog_history + [HumanMessage(content=user_input)],
     )
     return response.content
 
+
 """
 For information on how to customize the ChatInterface, peruse the gradio docs: https://www.gradio.app/docs/chatinterface
 """
@@ -28,9 +29,12 @@ demo = gr.ChatInterface(
     fn=respond,
     type="messages",
     additional_inputs=[
-        gr.Textbox(value="You are a friendly Chatbot.", label="System message"),
-        gr.Slider(minimum=1, maximum=2048, value=512, step=1, label="Max new tokens"),
-        gr.Slider(minimum=0.1, maximum=4.0, value=0.7, step=0.1, label="Temperature"),
+        gr.Textbox(value="You are a friendly Chatbot.",
+                   label="System message"),
+        gr.Slider(minimum=1, maximum=2048, value=512,
+                  step=1, label="Max new tokens"),
+        gr.Slider(minimum=0.1, maximum=4.0, value=0.7,
+                  step=0.1, label="Temperature"),
         gr.Slider(
             minimum=0.1,
             maximum=1.0,