fileseq.go
func IsFrameRange(frange string) bool {
	_, err := frameRangeMatches(frange)
	if err == nil {
		return true
	}
	return false
}
func IsFrameRange(frange string) bool {
	_, err := frameRangeMatches(frange)
	if err == nil {
		return true
	}
	return false
}
// IsFrameRange returns true if the given string is a valid frame
// range format.  Any padding characters, such as '#' and '@' are ignored.