1. What are the values of x, y and z after the code executes?  Why?

x = 10
y = 20
x = y
z = x
y = 15


2. Given the function definition below, which of the following are NOT legal/appropriate
calls to the function.  Explain.

def add_one(value):
    return value+1


a. add_one(10)
b. add_one()
c. add_one
d. add_one(-1)
e. add_one(2, 3)
f. add_one(16.1)
g. add_one("cs150 is great")