code: @Nonnull
    public PSExtends readExtendsFromXML (@Nonnull final IMicroElement eExtends)
    {
      final PSExtends ret = new PSExtends ();
  
      eExtends.forAllAttributes ( (sNS, sAttrName, sVal) -> {
        final String sAttrValue = _getAttributeValue (sVal);
        if (sAttrName.equals (CSchematronXML.ATTR_RULE))
          ret.setRule (sAttrValue);
        else
          ret.addForeignAttribute (sAttrName, sAttrValue);
      });
  
      eExtends.forAllChildElements (eChild -> {
        if (CSchematron.NAMESPACE_SCHEMATRON.equals (eChild.getNamespaceURI ()))
        {
          _warn (ret, "Unsupported Schematron element '" + eChild.getLocalName () + "'");
        }
        else
          _warn (ret, "Unsupported namespace URI '" + eChild.getNamespaceURI () + "'");
      });
      return ret;
    }
docs: Read an &lt;extends&gt; element
  
  @param eExtends
  The source micro element. Never <code>null</code>.
  @return The created domain object. May not be <code>null</code>.