def _create_dummy_frequencies(trips):
    """Create station stop frequencies."""
    for trip in trips:
        yield {'trip_id': trip['trip_id'], 'start_time': '04:30:00',
            'end_time': '08:30:00', 'headway_secs': '1200'}
        yield {'trip_id': trip['trip_id'], 'start_time': '08:30:00',
            'end_time': '20:30:00', 'headway_secs': '1800'}
        yield {'trip_id': trip['trip_id'], 'start_time': '20:30:00',
            'end_time': '25:30:00', 'headway_secs': '2800'}
