This is a cab fare calculator that takes four arguments and return the prospective fare.

The four arguments are as follows:
- City name (string e.g., 'San Francisco')
- Journey starting time (string, e.g. '13:40:07')
- Journey starting date (string, e.g. '2017-11-14')
- Journey duration in hours (int/float e.g., 4/4.5 )