code: func Hash(c interface{}, version int) (string, error) {
  	return fmt.Sprintf("v%d_%x", version, Md5(c, version)), nil
  }
docs: // Hash takes a data structure and returns a hash string of that data structure
  // at the version asked.
  //
  // This function uses md5 hashing function and default formatter. See also Dump()
  // function.