code: boolean popNamespace(String prefix)
      {
          // Prefixes "xml" and "xmlns" cannot be redefined
          if (prefix.startsWith(XML_PREFIX))
          {
              return false;
          }
  
          Stack stack;
          if ((stack = getPrefixStack(prefix)) != null)
          {
              stack.pop();
              return true;
          }
          return false;
      }
docs: Undeclare the namespace that is currently pointed to by a given prefix