Update app.py

app.py

@@ -34,7 +34,7 @@ def get_random_joke()-> str: #it's import to specify the return type
 def get_user_row(username: str) -> str:
     """A tool that fetches more information about the user in a .csv file.
     Args:
-        user_name: A string that's the user name.
+        username: A string that's the user name.
     """
 
     try: