i am stuck in the exercise pull it together

i have understood the logic of computing the total cost

i have defined each block with variables a, b,c

defined a function called add

and return a+b+c

but i get this error message , would be grateful for help

also ,

i am not understanding when we have defined a function forr city cost with arguements night then how do we change this arguement to days, ..

error message

"Oops, try again. trip_cost('Charlotte', 6) returned 220 instead of the correct value 1243"

```
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
else :
return plane_ride_cost
def rental_car_cost(days):
cost = 40 * days
if days >= 7:
cost -= 50
elif days >= 3:
cost -= 20
return cost
def trip_cost(city,days):
return rental_car_cost(days)
return hotel_cost(days)
return plane_ride_cost(city)
a=rental_car_cost(days)
b=hotel_cost(days)
c=plane_ride_cost(city)
def add(a,b,c):
return a+b+c
```