func ParseIdentifier(s string) (Identifier, error) {
	id, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		return 0, err
	}
	return Identifier(id), nil
}
ParseIdentifier converts a string into an identifier
package snomed
import (
	"fmt"
	"strconv"
	"github.com/wardle/go-terminology/verhoeff"
)
type Identifier int64