def scaled(target, prop, factor):
    """
    Scales an existing value by a factor.  Useful for constricting some throat
    property.

    Parameters
    ----------
    target : OpenPNM Object
        The object which this model is associated with. This controls the
        length of the calculated array, and also provides access to other
        necessary properties.

    prop : string
        The dictionary key of the array containing the values to be scaled.

    factor : scalar
        The factor by which the values should be scaled.

    Returns
    -------
    value : NumPy ndarray
        Array containing ``target[prop]`` values scaled by ``factor``.

    """
    value = target[prop] * factor
    return value
