def evalf(self, prec=None, **options):
        vec = self.zero
        for k, v in self.components.items():
            vec += v.evalf(prec, **options) * k
        return vec
Test that array migrations are frozen as I expect.
dataset/ETHPy150Open sympy/sympy/sympy/vector/basisdependent.py/BasisDependent.evalf--crossover with--dataset/ETHPy150Open lukesneeringer/django-pgfields/tests/south_migrations/tests.py/MigrationCreationSuite.test_array_freeze