public Builder end(){
  if (ends.isEmpty())   throw new IllegalStateException("No pending tag/section to close.");
  html.a(ends.pop());
  return this;
}

public Builder end ( ) { if ( ends . isEmpty ( ) ) throw new IllegalStateException ( "No pending tag/section to close." ) ; html . a ( ends . pop ( ) ) ; return this ; }
closes the last opened tag or section .
