“Chained” Conditional Statement

if test1:
      action1_block
elif test2:
      action2_block
elif test3:
      action3_block
else:
      else_action_block

def ticket_cost(age):
      if age < 3:
            cost = 0.0
      elif age < 18:
            cost = 5.50
      elif age < 65:             cost = 9.25
      else:
            cost = 8.00
      return cost

Factorial Function

## factorial(x) produces the product ## of all the integers from 1 to n ## factorial: Nat -> Nat
## example:
## factorial(5) => 120 ## factorial(0) => 1 def factorial (x):
      if x == 0:
            return 1
      else:
      return x * factorial( x - 1)

Limitations

factorial(1000) -> RuntimeError: maximum recursion depth exceeded

• There is a limit to how much recursion Python “can remember”

Important

If a function does not include a return statement, then the produced value (and type) is None

• The purpose statement does not need to include “Produces None” as this will be included in the contract.