code: def list_permissions(self, file_id):
          
          url = '{0}/{1}/permissions'.format(DRIVE_FILES_API_V2_URL, file_id)
  
          r = self.request('get', url)
  
          return r.json()['items']
docs: Retrieve a list of permissions for a file.
  
          :param file_id: a spreadsheet ID (aka file ID.)
          :type file_id: str