acket'>[</span><span class='id identifier rubyid_key'>key</span><span class='rbracket'>]</span>
  <span class='kw'>end</span>
  <span class='comment'># Undefine keys that were not there previously
</span>  <span class='id identifier rubyid_newly_defined_keys'>newly_defined_keys</span><span class='period'>.</span><span class='id identifier rubyid_each'>each</span> <span class='lbrace'>{</span> <span class='op'>|</span><span class='id identifier rubyid_key'>key</span><span class='op'>|</span> <span class='con