Godeps/_workspace/src/gopkg.in/mgo.v2/bson/bson.go
func ObjectIdHex(s string) ObjectId {
	d, err := hex.DecodeString(s)
	if err != nil || len(d) != 12 {
		panic(fmt.Sprintf("Invalid input to ObjectIdHex: %q", s))
	}
	return ObjectId(d)
}
func ObjectIdHex(s string) ObjectId {
	d, err := hex.DecodeString(s)
	if err != nil || len(d) != 12 {
		panic(fmt.Sprintf("Invalid input to ObjectIdHex: %q", s))
	}
	return ObjectId(d)
}
// ObjectIdHex returns an ObjectId from the provided hex representation.
// Calling this function with an invalid hex representation will
// cause a runtime panic. See the IsObjectIdHex function.