After crash google-chrome start in window mode

Question

I have some python script whitch I start on server debian 9 from difrent user, whitch i created by command useradd in xvfb session:

su -l username -c 'xvfb-run -a --server-args="-screen 0 1240x1024x24" python /path/to/python_script.py'

in scrip i start google-chrome and do some actions for test:

import webbrowser
controller = webbrowser.get('google-chrome').open('site_url')
...

But after crash in some users google-chrome begin started in window mode (not full screen) see screenshot:

How can i fix it by using python? I already try to send ALTLEFT + F10 etc. by pyautogui :

impotr pyautogui
pyautogui.hotkey('altleft', 'f10') - no result

also try:

pyautogui.hotkey('f11') - no result

and start chrome-browser with key --kiosk:

webbrowser.get('/usr/bin/google-chrome --kiosk') - got exception

Update: Exception is:

Traceback (most recent call last):
File "/path/to/python_script.py", line 519, in
<module>youtube_clicker.main()
File "/path/to/python_script.py", line 450, in main
self.controller.open_new("https://site.url")
File "/usr/lib/python2.7/webbrowser.py", line 151, in open_new
return self.open(url, 1)
File "/usr/lib/python2.7/webbrowser.py", line 275, in open
success = self._invoke(args, True, autoraise)
File "/usr/lib/python2.7/webbrowser.py", line 238, in _invoke
stderr=inout, preexec_fn=setsid)
File "/usr/lib/python2.7/subprocess.py", line 390, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1024, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory