sequence.go
func (s *FileSequence) SetPaddingStyle(style PadStyle) {
	s.padMapper = padders[style]
	s.SetPadding(s.padMapper.PaddingChars(s.ZFill()))
}
func (s *FileSequence) SetPaddingStyle(style PadStyle) {
	s.padMapper = padders[style]
	s.SetPadding(s.padMapper.PaddingChars(s.ZFill()))
}
// Set a new padding style for mapping between characters and
// their numeric width