code: def test_scalar_move_preloaded(self):
      User, Address = self.classes.User, self.classes.Address
  
      sess = fixture_session()
      a1 = Address(email_address="address1")
      a2 = Address(email_address="address1")
      u1 = User(name="jack", address=a1)
  
      sess.add_all([u1, a1, a2])
      sess.commit()  # everything is expired
  
      # load a1.user
      a1.user
  
      # reassign
      a2.user = u1
  
      # backref fires
      assert u1.address is a2
  
      # stays on both sides
      assert a1.user is u1
      assert a2.user is u1
  
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 3 for calling the O2OScalarBackrefMoveTest obj's underlying member method code with example usage: obj.test_scalar_move_preloaded() without return types