docs: def _close(self):
          '''
          Closes aiohttp session and all open file descriptors
          '''
          if hasattr(self, 'aiohttp'):
              if not self.aiohttp.closed:
                  self.aiohttp.close()
          if hasattr(self, 'file_descriptors'):
              for fd in self.file_descriptors.values():
                  if not fd.closed:
                      fd.close()