code: def setup_mappers(cls):
      keywords, items, item_keywords, Keyword, Item = (
          cls.tables.keywords,
          cls.tables.items,
          cls.tables.item_keywords,
          cls.classes.Keyword,
          cls.classes.Item,
      )
  
      cls.mapper_registry.map_imperatively(
          Item,
          items,
          properties={
              "keywords": relationship(
                  Keyword, secondary=item_keywords, backref="items"
              )
          },
      )
      cls.mapper_registry.map_imperatively(Keyword, keywords)
  
imports: from sqlalchemy import testing
  from sqlalchemy import text
  from sqlalchemy.orm import attributes
  from sqlalchemy.orm import backref
  from sqlalchemy.orm import relationship
  from sqlalchemy.orm import Session
  from sqlalchemy.testing import eq_
  from sqlalchemy.testing import is_
  from sqlalchemy.testing.fixtures import fixture_session
  from test.orm import _fixtures
label_desc: Use image node_id 1 for calling the M2MCollectionMoveTest obj's underlying member method code with example usage: obj.setup_mappers(cls) without return types