# function definition, where the function hi takes 0 parameter
def hi():
    print("howdy")
    print("hi there")
    
# call/invoke the function
hi()

# function defined that takes 1 parameter
def bye(n):
    print("goodbye", n)

bye("tali")
bye("naomi")

x = bye("heather") # store what is returned from function in x
print(x) # prints None, because nothing was returned from function

# define a function that takes 2 parameters and adds them together
def add(x, y):
    z = x + y
    return z

mysum = add(42, 100)
print(mysum)