안녕하세요 python selenium 실습중인데 왜 랜덤함수가 작동하지 않을까요?

#만약에 박지성이 처음 나오면 계속 박지성만 나오게 됩니다.
#이유가 뭘까요??

# -*- coding: utf-8 -*-
"""
Created on Tue Apr 23 22:18:31 2019

@author: Administrator

"""
from selenium import webdriver
import time
import random

# 구분값

serch_num = random.randrange(0,2)
time_serch = random.randrange(0,2)
def serch_names(item):
babo = driver.find_element_by_id("query")
babo.send_keys(item)
babo = driver.find_element_by_id("search_btn")
babo.click()
return item
for x in range(10):
# 검색창 검색
driver = webdriver.Chrome('C:\chromedriver.exe')
driver.get('http://www.naver.com')

if serch_num == 0:
serch_names('박지성')
babo = driver.find_element_by_id("nx_query")
time.sleep(time_serch)
babo.send_keys('맨유')
driver.close()
elif serch_num ==1:
serch_names('손흥민')
babo = driver.find_element_by_id("nx_query")
time.sleep(time_serch)
babo.send_keys('토트넘')
driver.close()
elif serch_num ==2:
serch_names('설기현')
babo = driver.find_element_by_id("nx_query")
time.sleep(time_serch)
babo.send_keys('레딩')
driver.close()