code: def delete_all(self):
          '''Delete all books from the index'''
          def delete_action_gen():
              scanner = scan(self.es,
                             index=self.index_name,
                             query={'query': {'match_all':{}}})
              for v in scanner:
                  yield { '_op_type': 'delete',
                          '_index': self.index_name,
                          '_type': v['_type'],
                          '_id': v['_id'],
                        }
          bulk(self.es, delete_action_gen()f delete_all(self):
          '''Delete all books from the index'''
          def delete_action_gen():
              scanner = scan(self.es,
                             index=self.index_name,
                             query={'query': {'match_all':{}}})
              for v in scanner:
                  yield { '_op_type': 'delete',
                          '_index': self.index_name,
                          '_type': v['_type'],
                          '_id': v['_id'],
                        }
          bulk(self.es, delete_action_gen())
docs: Delete all books from the index