I figured out how to get my code up and running. Sweet.
Only through some trial and error. Here's my question: When I use sum() to return the values of the three functions, it returns and error message saying that the code expected to return two arguments, and instead got three (which I'm assuming is the three functions).
def trip_cost(city, days): return sum(rental_car_cost(days), plane_ride_cost(city),hotel_cost(days))
Error message reads as:
trip_cost('Tampa', 9) raised an error: sum expected at most 2 arguments, got 3
Then I changed the code to
def trip_cost(city, days): return rental_car_cost(days) + plane_ride_cost(city)+ hotel_cost(days)
And it passed. Can anyone shed some light on this?