code: public static SwipeBack attach(Activity activity, Type type,
  			Position position, int dragMode) {
  		return attach(activity, type, position, dragMode,
  				new DefaultSwipeBackTransformer());
  	}
docs: Attaches the SwipeBack to the Activity
  
  @param activity
  @param type
  @param position
  @param dragMode
  The dragMode which is {@link #DRAG_CONTENT} or
  {@link #DRAG_WINDOW}
  @return The created SwipeBack instance