""" a demo of what a 'decorator' is in python """

def debugit(func):
    def debugged(x,y):
        print(" x is ", x)
        print(" y is ", y)
        return func(x, y)
    return debugged

@debugit
def f(x, y):
    return 2*x + 3*y

answer = f(10, 20)    # turns into (debugit(f))(x,y)
print("answer is ", answer)