o  You cannot delete generation 1 of an element.
    o  You cannot delete a generation that has variants off it.
    o  You cannot delete a generation that has a review pending.
    o  You cannot delete a generation that is reserved.
    o  You cannot delete a generation that is in a class.
    o  All generations in the specified range of generations to be
       deleted must be on the same line of descent.
    o  You cannot use /GENERATION in combination with /AFTER, /BEFORE,
       /FROM, or /TO.
    o  You cannot specify /AFTER and /FROM on the same command line.
    o  You cannot specify /BEFORE and /TO on the same command line.