docs: def add_entity_meta(self, datastream, options, data):
          """
          To add entity meta data to a datastream
          :param datastream: string
          :param options: dict
          :param data: list
          """
          url = '/datastream/' + str(datastream) + '/entityMeta'
          response = self.http.post(url, data)
          entityMetaList = []
          for entityMeta in response:
              entityMetaList.append(Schemas.EntityMeta(entityMeta=entityMeta))
          return entityMetaList