Update app.py

app.py

@@ -50,7 +50,7 @@ class WeatherInput(BaseModel):
 def get_weather_by_location(city: str = None):
     """Get the weather based on the user's location if no city is specified."""
 
-    if city=='':
+    if (city == '') or (city == None) or (not city):
         location = get_location_from_ip()
         city = location['city']