Browsing context has been discarded

I tried to run it and received: selenium.common.exceptions.NoSuchWindowException: Message: Browsing context has been discarded

~/UdemyCourseGrabber# python3 main.py
Paste in your Udemy course URL: https://www.udemy.com/course/modern-javascript-from-novice-to-ninja/
Traceback (most recent call last):
  File "main.py", line 13, in <module>
    course_info = get_info(udemy_url)
  File "/root/UdemyCourseGrabber/functions.py", line 248, in get_info
    course_name = get_course_name(udemy_url)
  File "/root/UdemyCourseGrabber/functions.py", line 15, in get_course_name
    browser.find_element_by_css_selector(".btn-primary > span:nth-child(1)")
  File "/usr/local/lib/python3.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 598, in find_element_by_css_selector
    return self.find_element(by=By.CSS_SELECTOR, value=css_selector)
  File "/usr/local/lib/python3.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 978, in find_element
    'value': value})['value']
  File "/usr/local/lib/python3.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 321, in execute
    self.error_handler.check_response(response)
  File "/usr/local/lib/python3.7/dist-packages/selenium/webdriver/remote/errorhandler.py", line 242, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.NoSuchWindowException: Message: Browsing context has been discarded

Great work, please keep it up. Thank you.