question: public Builder addSubButton ( Context context , int drawable , int [ ] twoColors ) { if ( drawables == null ) drawables = new ArrayList < > ( ) ; drawables . add ( ContextCompat . getDrawable ( context , drawable ) ) ; if ( colors == null ) colors = new ArrayList < > ( ) ; colors . add ( twoColors ) ; return this ; }
target:  Add a sub button with 3 params.