```
def hotel_cost(nights):
return 140*nights
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
def rental_car_cost(days):
if days >= 7:
return ((days*40) - 50)
elif days >= 3:
return ((days*40) - 20)
elif days < 3 and days >= 0:
return days*40
def trip_cost(days, city):
return rental_car_cost(days) + hotel_cost(days) + plane_ride_cost(city)
```

**Why am I getting an error on this?**