def METHOD_NAME(self):
    def m2m_with_instrumentedlist():
        from anyblok import Declarations
        Model = Declarations.Model
        @Declarations.register(Model)
        class Test:
            id = Integer(primary_key=True)
        @Declarations.register(Model)
        class Test2:
            id = Integer(primary_key=True)
            tests = Many2Many(model=Model.Test, many2many="tests2")
    registry = self.init_registry(m2m_with_instrumentedlist)
    t = registry.Test.insert()
    t2 = registry.Test2.insert()
    t.tests2.append(t2)
    assert t2.tests == [t]
    check = isinstance(t.tests2, registry.InstrumentedList)
    assert check
    check = isinstance(t2.tests, registry.InstrumentedList)
    assert check