code: def get_key(self, key_id):
          
          url = ENCRYPTION_KEY_URL.format(key_id)
          return self._key_from_json(self._get_resource(url))
docs: Returns a restclients.Key object for the given key ID.  If the
          key ID isn't found, or if there is an error communicating with the
          KWS, a DataFailureException will be thrown.