code: def test_backref_pop_m2o(self):
      User, Address = self.classes.User, self.classes.Address
  
      u1 = User()
      u2 = User()
      a1 = Address()
      u1.addresses.append(a1)
      u2.addresses.append(a1)
  
      # a1 removed from u1.addresses as of [ticket:2789]
      assert a1 not in u1.addresses
  
      assert a1.user is u2
      assert a1 in u2.addresses
  
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 2 for calling the O2MStaleBackrefTest obj's underlying member method code with example usage: obj.test_backref_pop_m2o() without return types