def increment (x):
    return x + 1

def double(x):
    return x * 2


for i in range(10):
    print(i)

def run_twice(func, arg):
    return func(func(arg))


def rec_print(n):
    print(n)
    if n>0:
        rec_print(n-1)

def add(x, y):
    return x + y

def identity(x):
    return x


def map()
