问Python3.5:我收到了一个错误："NameError:未定义名称'multiprocessing‘“

EN

    pool = multiprocessing.Pool(5)
NameError: name 'multiprocessing' is not defined

from multiprocessing import Pool
from selenium.common.exceptions import TimeoutException
from bs4 import BeautifulSoup
from selenium import webdriver

if __name__ == '__main__':
    driver = webdriver.Firefox()
    driver.get("https://www.facebook.com/")
    driver.find_element_by_css_selector("#email").send_keys("myemail@gmail.com")
    driver.find_element_by_css_selector("#pass").send_keys("mypassword")
    driver.find_element_by_css_selector("#u_0_m").click()

    pool = multiprocessing.Pool(5)
    pool.map(friend_uid_list, uid_list)