I've got stucked here... been looking for the error but can't find it! some help pls!!!
Here is the link to the exercise (pull it together) https://www.codecademy.com/courses/python-beginner-P5YtY/1/4?curriculum_id=4f89dab3d788890003000096#
Here goes the error code "Oops, try again. trip_cost('Pittsburgh', 1) raised an error: cannot concatenate 'str' and 'NoneType' objects"
I thought it should work properly
#Hotel def hotel_cost(nights): return 140 * nights #Plane def plane_ride_cost(city): if city == "Charlotte": return 183 elif city == "Tampa": return 220 elif city == "Pittsburgh": return 222 elif city == "Los Angeles": return 475 #Car def rental_car_cost(days): if days >= 7: return (days * 40) - 50 elif days >= 3: return (days * 40) - 20 else: return days * 40 #Total Cost def trip_cost(days, city): return hotel_cost(days) + plane_ride_cost(city) + rental_car_cost(days)