code: def get_metadata(self, identifier, request_kwargs=None):
          
          request_kwargs = {} if not request_kwargs else request_kwargs
          url = '{0}//archive.org/metadata/{1}'.format(self.protocol, identifier)
          if 'timeout' not in request_kwargs:
              request_kwargs['timeout'] = 12
          try:
              resp = self.get(url, **request_kwargs)
              resp.raise_for_status()
          except Exception as exc:
              error_msg = 'Error retrieving metadata from {0}, {1}'.format(url, exc)
              logger.error(error_msg)
              raise type(exc)(error_msg)
          return resp.json()
docs: Get an item's metadata from the `Metadata API
          <http://blog.archive.org/2013/07/04/metadata-api/>`__
  
          :type identifier: str
          :param identifier: Globally unique Archive.org identifier.
  
          :rtype: dict
          :returns: Metadat API response.