import multiprocessing
import functools

def compose(*functions):
    return functools.reduce(lambda f, g: lambda x: f(g(x)), functions, lambda x: x

twox = lambda x: 2*x
operation = compose(*funcs)
nums = range(10)

p = multiprocessing.Pool(processes=3)
p.map(operation, nums) ## raises an AttributeError

def wrapped_operation(x):
    return operation(x)

p = multiprocessing.Pool(processes=3)
p.map(wrapped_operation, nums) ## returns [0,8,16,...]