def METHOD_NAME(fleet_of_highperf_mocked_ursulas,
                                            highperf_mocked_alice,
                                            highperf_mocked_bob):
    mocks = (
        mock_secret_source(),
        mock_cert_loading,
        mock_metadata_validation,
        mock_message_verification,
        )
    with contextlib.ExitStack() as stack:
        for mock in mocks:
            stack.enter_context(mock)
        policy = highperf_mocked_alice.grant(
            highperf_mocked_bob, b"any label", threshold=20, shares=30,
            expiration=maya.when('next week'))
    # TODO: Make some assertions about policy.
    total_verified = sum(node.verified_node for node in highperf_mocked_alice.known_nodes)
    # Alice may be able to verify more than `n`, but certainly not less,
    # otherwise `grant()` would fail.
    assert total_verified >= 30
    _POLICY_PRESERVER.append(policy)