def METHOD_NAME():
    """Get unique photometer interface classes presently available.
    This is used to preserve compatibility with the legacy
    :func:`~psychopy.hardware.getAllPhotometers()` function call.
    Returns
    -------
    list
        Discovered unique photometer classes.
    """
    # iterate over known photometers
    photometers = getAllPhotometers()
    if not photometers:  # do nothing if no photometers found
        return []
    interfaceIDs = []  # a store unique IDs for interfaces
    # Remove items the are duplicated, i.e. multiple IDs that have a common
    # interface.
    knownInterfaces = []
    for cls in photometers.values():
        clsID = id(cls)
        if clsID in interfaceIDs:  # already added
            continue
        interfaceIDs.append(clsID)
        knownInterfaces.append(cls)
    return knownInterfaces