common.go
func (f *formatifier) removeNonDigits() {
	rp := regexp.MustCompile(`\D`)
	f.theString = rp.ReplaceAllString(f.theString, "")
}
func (f *formatifier) removeNonDigits() {
	rp := regexp.MustCompile(`\D`)
	f.theString = rp.ReplaceAllString(f.theString, "")
}
// removeNonDigits removes any non digit characters from the string.