Selenium - Upload a file

#wd-upload-file.py

from selenium import webdriver
from selenium.webdriver.remote.webelement import WebElement
from selenium.common.exceptions import NoSuchElementException
import os.path


def upload_files(element, *files):
    driver = element.parent
    isLocal = not driver._is_remote or '127.0.0.1' in driver.command_executor._url
    paths = []
    
    # ensure files are present, and upload to the remote server if session is remote
    for file in files :
        if not os.path.isfile(file) :
            raise FileNotFoundError(file)
        paths.append(file if isLocal else element._upload(file))
    
    # intercept the file input from the click event and disable the file picker from the OS
    driver.execute_script("""\
var element = arguments[0];
window.wd1b2ce5c94f7c = null;
element.ownerDocument.addEventListener('click', function handler(event) {
  if (event.target.type === 'file') {
    element.ownerDocument.removeEventListener('click', handler, true);
    window.wd1b2ce5c94f7c = event.target;
    event.preventDefault();
    event.stopPropagation();
  }
}, true);
        """, element)
    
    # trigger a click which should propagate to the file input (same as pressing enter)
    element.click()
    
    # get the file input that received the click
    elm_input = driver.execute_script("return window.wd1b2ce5c94f7c;")
    if elm_input is None :
      raise NoSuchElementException("Failed to detect the file input")
    
    # assign the files to the file input
    value = '\n'.join(paths)
    elm_input._execute('sendKeysToElement', {'value': [value], 'text': value})

WebElement.upload_files = upload_files


############################# USAGE EXAMPLE #############################

driver = webdriver.Chrome()
driver.get("https://react-dropzone.js.org/")

driver.find_element_by_css_selector(".dropzone > *")\
    .upload_files('c:\\temp\\image1.png')

what is window.wd1b2ce5c94f7c;? because I received a NoSuchElementException result.