code: func CheckVersion(version int32) {
  	if version < PACKED_VERSION_START {
  		panic(fmt.Sprintf("Version is too old, should be at least %v (got %v)", PACKED_VERSION_START, version))
  	} else if version > VERSION_CURRENT {
  		panic(fmt.Sprintf("Version is too new, should be at most %v (got %v)", VERSION_CURRENT, version))
  	}
  }
docs: // Ceck the validity of a version number