ound</code></em> may be either a string
   that is valid input for the subtype, or empty to indicate no
   lower bound.  Likewise, <em class="replaceable"><code>upper-bound</code></em> may be
   either a string that is valid input for the subtype, or empty to
   indicate no upper bound.
  </p><p>
   Each bound value can be quoted using <code class="literal">"</code> (double quote)
   characters.  This is necessary if the bound value contains parentheses,
   brackets, commas, double quotes, or backslashes, s