func (s *FrameSet) Index(frame int) int {
	return s.rangePtr.Index(frame)
}
func (s *FrameSet) Index(frame int) int {
	return s.rangePtr.Index(frame)
}
func ( s * FrameSet ) Index ( frame int ) int { return s . rangePtr . Index ( frame ) }
// Index returns the index position of the frame value
// within the frame set.
// If the given frame does not exist, then return -1
Index returns the index position of the frame value within the frame set . If the given frame does not exist then return - 1