public async Task TestModifyPolicyAsync()
        {
            var e = new Enforcer(_testModelFixture.GetNewRbacTestModel());

            e.BuildRoleLinks();

            TestGetPolicy(e, AsList(
                              AsList("alice", "data1", "read"),
                              AsList("bob", "data2", "write"),
                              AsList("data2_admin", "data2", "read"),
                              AsList("data2_admin", "data2", "write")));

            await e.RemovePolicyAsync("alice", "data1", "read");

            await e.RemovePolicyAsync("bob", "data2", "write");

            await e.RemovePolicyAsync("alice", "data1", "read");

            await e.AddPolicyAsync("eve", "data3", "read");

            await e.AddPolicyAsync("eve", "data3", "read");

            var namedPolicy = AsList("eve", "data3", "read");
            await e.RemoveNamedPolicyAsync("p", namedPolicy);

            await e.AddNamedPolicyAsync("p", namedPolicy);

            TestGetPolicy(e, AsList(
                              AsList("data2_admin", "data2", "read"),
                              AsList("data2_admin", "data2", "write"),
                              AsList("eve", "data3", "read")));

            await e.RemoveFilteredPolicyAsync(1, "data2");

            TestGetPolicy(e, AsList(AsList("eve", "data3", "read")));
        }