Ошибка FileNotOpenedError

Question

Я получаю сообщение об ошибке при попытке записать файл в облачное хранилище

мой код:

---

my_file = files.gs.create('/gs/foo/myfile')
with files.open(my_file, 'a') as f:
  f.write('Hello World!')
  f.write('Hello World Again!')

---

Traceback (most recent call last):
  File "C:\Datos\proyectos\dropbox\Proyectos\as3\semtable\remote_api\using_datastore.py", line 63, in <module>
    f.write('Hello World Again!')
  File "C:\Program Files\Google\google_appengine\google\appengine\api\files\file.py", line 281, in __exit__
    self.close()
  File "C:\Program Files\Google\google_appengine\google\appengine\api\files\file.py", line 275, in close
    self._make_rpc_call_with_retry('Close', request, response)
  File "C:\Program Files\Google\google_appengine\google\appengine\api\files\file.py", line 388, in _make_rpc_call_with_retry
    _make_call(method, request, response)
  File "C:\Program Files\Google\google_appengine\google\appengine\api\files\file.py", line 236, in _make_call
    _raise_app_error(e)
  File "C:\Program Files\Google\google_appengine\google\appengine\api\files\file.py", line 179, in _raise_app_error
    raise FileNotOpenedError()
google.appengine.api.files.file.FileNotOpenedError