Class KeyMetaData -superclass Set/KeySetKeyMetaData instproc metatostring {} {        return [$self settolist]}KeyMetaData instproc stringtometa {l} {        $self addlist $l}KeyMetaData instproc maptosize {} {    # By default, the size of the data is 500 times the number    # of elements of meta-data    set els [$self numelements]    return [expr $els * 500]}Class ListMetaData -superclass KeyMetaDataListMetaData instproc getkey {element} {        return [lindex $element 0]}