Update app.py

app.py

@@ -32,7 +32,10 @@ def get_current_time_in_timezone(timezone: str) -> str:
 
 @tool
 def guess_city_for_timezone(timezone: str) -> str:
-    # Could do a minimal lookup or a real search, for example:
+    '''A tool to guess a city in a timezone
+    Args:
+        timezone:  A string representing a valid timezone (e.g., 'America/New_York').
+    '''
     known_timezones_to_cities = {
         "America/Los_Angeles": "Los Angeles",
         "America/New_York": "New York",