def rf_duration(rf_event, dt):
    """Return the duration of the rf event (array) based on the number of the points and  dt.

    Args:
        rf_event (np.array): An array of event.
        dt (float [s]): Value of time resolution.

    Returns:
        float [s]: duration of the event.

    Todo:
        Regard the dimensions of the array.

    """
    size = rf_event.size
    return size * dt
