File "par.py", line 27, in download_collection
    for el in cursor:
  File "/home/kokeso/.local/lib/python3.5/site-packages/pymongo-3.8.0.dev0-py3.5-linux-x86_64.egg/pymongo/cursor.py", line 1189, in next
    if len(self.__data) or self._refresh():
  File "/home/kokeso/.local/lib/python3.5/site-packages/pymongo-3.8.0.dev0-py3.5-linux-x86_64.egg/pymongo/cursor.py", line 1126, in _refresh
    self.__send_message(g)
  File "/home/kokeso/.local/lib/python3.5/site-packages/pymongo-3.8.0.dev0-py3.5-linux-x86_64.egg/pymongo/cursor.py", line 982, in __send_message
    helpers._check_command_response(first)
  File "/home/kokeso/.local/lib/python3.5/site-packages/pymongo-3.8.0.dev0-py3.5-linux-x86_64.egg/pymongo/helpers.py", line 152, in _check_command_response
    raise CursorNotFound(errmsg, code, response)