def copy(self, other):
        self.columnlist = other.columnlist
        UnaryOperator.copy(self, other)
AddField should NOT optimize into CreateModel if it's an M2M using a
dataset/ETHPy150Open uwescience/raco/raco/algebra.py/PartitionBy.copy--crossover with--dataset/ETHPy150Open django/django/tests/migrations/test_optimizer.py/OptimizerTests.test_create_model_add_field_not_through_m2m_through