def keylist(self):
        """Return a list of names in order by value."""
        items = self.enumerations.items()
        items.sort(lambda a, b: self.cmp(a[1], b[1]))

        # last item has highest value
        rslt = [None] * (items[-1][1] + 1)

        # map the values
        for key, value in items:
            rslt[value] = key

        # return the result
        return rslt
Return a list of names in order by value.