public T addStyle(Style style){
  if (styles == null) {
    styles=new LinkedHashSet<>();
  }
  styles.add(style);
  return (T)(Object)this;
}

public T addStyle ( Style style ) { if ( styles == null ) { styles = new LinkedHashSet < > ( ) ; } styles . add ( style ) ; return ( T ) ( Object ) this ; }
add a new style to this element . a style can be used as an effective way to define multiple equal properties to several elements .
