"""
 example of a decorator
"""

def debug_it(f):
    def f_debug(x):
        value = f(x)
        print(f"debug: {f.__name__}({x}) = {value})")
        return value
    return f_debug

@debug_it
def twice_plus_one(y):
    return 2*y+1

def main():
    print(sum([twice_plus_one(i) for i in range(10)]))

main()