code: protected SimpleOutputElement createChild(String localName)
      {
          /* At this point we can also discard attribute Map; it is assumed
           * that when a child element has been opened, no more attributes
           * can be output.
           */
          mAttrSet = null;
          return new SimpleOutputElement(this, null, localName,
                                         mDefaultNsURI, mNsMapping);
      }
docs: Simplest factory method, which gets called when a 1-argument
  element output method is called. It is, then, assumed to
  use the default namespce.