def METHOD_NAME(self, model):
    orig_fixed_vars = fixed_variables_set(model)
    orig_act_consts = activated_constraints_set(model)
    model.props.initialize(optarg={"tol": 1e-6})
    assert degrees_of_freedom(model) == 0
    fin_fixed_vars = fixed_variables_set(model)
    fin_act_consts = activated_constraints_set(model)
    assert len(fin_act_consts) == len(orig_act_consts)
    assert len(fin_fixed_vars) == len(orig_fixed_vars)
    for c in fin_act_consts:
        assert c in orig_act_consts
    for v in fin_fixed_vars:
        assert v in orig_fixed_vars