18. Sum of Three

# Define a procedure, sum3, that takes three
# inputs, and returns the sum of the three
# input numbers.
# To help you out, the code for sum(a,b) is below.

def sum(a,b):
    return a + b







#print sum3(1,2,3)
#>>> 6

#print sum3(93,53,70)
#>>> 216