Как загрузить файл с помощью selenium webdriver с python

Это следующий сценарий, который я пробовал. Здесь сценарий передается, но файл не загружается:

import unittest
from selenium import webdriver
import time
import os
from selenium.webdriver.common.keys import Keys
from selenium .webdriver.common.action_chains import ActionChains

class notaryfileupload(unittest.TestCase):

    def setUp(self):
        self.driver=webdriver.Chrome()

    def test_Notaryfileupload(self):
        driver=self.driver
        driver.get("https://mtsdev.westus.cloudapp.azure.com/#")
        time.sleep(30)
        username=driver.find_element_by_xpath("//*[@id='login-form-username']")
        username.send_keys("[email protected]")
        driver.implicitly_wait(4)
        password=driver.find_element_by_xpath("//*[@id='login-form-password']")
        password.send_keys("Mindtech@2017")
        driver.implicitly_wait(4)
        submit=driver.find_element_by_xpath("//*[@id='login-form-submit']")
        submit.click()
        driver.implicitly_wait(8)
        driver.maximize_window()
        time.sleep(5)
        searchbox=driver.find_element_by_xpath("//*[@id='content']/div/div[2]/div[1]/div[1]/div/div/input")
        searchbox.send_keys("BN0000023")
        time.sleep(15)
        click=driver.find_element_by_xpath("//*[@id='content']/div/div[2]/table/tbody/tr[1]/td[1]/span")
        click.click()
        time.sleep(20)
        driver.refresh()
        time.sleep(20)
        driver.execute_script("window.scrollTo(0, document.body.scrollHeight);")
        time.sleep(6)
        driver.execute_script("window.scrollBy(0, -550);")
        time.sleep(6)
        attachment=driver.find_element_by_xpath("//*[@id='content']/data-ng-form/div/div[2]/div[8]/div/work-area-template/div/div[2]/div[2]/table/thead/tr[2]/th/div/div/input[2]")
       # driver.execute_script('arguments[0].style = ""; arguments[0].style.display = "block"; arguments[0].style.visibility = "visible";', attachment)
        attachment.send_keys("C:\Users\vignesh\Desktop\New folder\comments.txt")
        time.sleep(30)


    def tearDown(self):
      self.driver.quit()

if __name__ == '__main__':
    unittest.main()
#attachment=driver.find_element_by_name("multifile-939[]")
#attachment.send_keys("C:\Users\vigne\Desktop\important pyton\dental.txt")