def sanitize_focus!(from_parent)
      if @focus >= focusable.size
        @focus = focusable.size - 1
        return false if from_parent

      elsif @focus < 0
        @focus = 0
        return false if from_parent
      end

      true
    end
def sanitize_focus!(from_parent)
      if @focus >= focusable.size
        @focus = focusable.size - 1
        return false if from_parent

      elsif @focus < 0
        @focus = 0
        return false if from_parent
      end

      true
    end
Internal helper, sanitize the focus tracker.
 Return value indicates if sanity is preseved
 in the context of this component (else we will
 return to parent)