1. Write a function orderPizza that allows the user input to build a pizza.  It then prints a thank you message, the cost of the pizza and then returns the Pizza that was built.

>>> orderPizza()

Welcome to Python Pizza!

What size pizza would you like (S,M,L): M

Type topping to add (or Enter to quit): mushroom

Type topping to add (or Enter to quit): onion

Type topping to add (or Enter to quit): garlic

Type topping to add (or Enter to quit): 

Thanks for ordering!

Your pizza costs $14.299999999999999

Pizza('M',{'mushroom', 'onion', 'garlic'})

>>> orderPizza()

Welcome to Python Pizza!

What size pizza would you like (S,M,L): L

Type topping to add (or Enter to quit): calamari

Type topping to add (or Enter to quit): garlic

Type topping to add (or Enter to quit): 

Thanks for ordering!

Your pizza costs $16.65

Pizza('L',{'garlic', 'calamari'})

>>> p=orderPizza()

Welcome to Python Pizza!

What size pizza would you like (S,M,L): S

Type topping to add (or Enter to quit): 

Thanks for ordering!

Your pizza costs $6.25

>>> p

Pizza('S',set())

>>>