xvfbwrapper无法正常工作

Question

我想在不打开浏览器的情况下运行python selenium脚本。我在rhel上安装了xvfbwrapper-0.1.3，并编辑了我的代码：

from selenium import webdriver,selenium
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import Select
from selenium.common.exceptions import NoSuchElementException
import unittest, time
from xvfbwrapper import Xvfb


class SeleTry(unittest.TestCase):
   def setUp(self):
        try:
            vdisplay = Xvfb(width=1280, height=720)
            vdisplay.start()
            self.driver = webdriver.Firefox()
            self.driver.implicitly_wait(10)
         .....//rest of the code//

当我试图执行它时，它正在抛出一个皇帝：

 'The browser appears to have exited before we could connect. The output was: Error: cannot open display: :1013\n'

由于我是新手，我不知道我错了什么？