docs: def GetArtifact(self, name):
      """Get artifact by name.
  
      Args:
        name: artifact name string.
  
      Returns:
        artifact object.
      Raises:
        ArtifactNotRegisteredError: if artifact doesn't exist in the registy.
      """
      self._CheckDirty()
      result = self._artifacts.get(name)
      if not result:
        raise rdf_artifacts.ArtifactNotRegisteredError(
            "Artifact %s missing from registry. You may need to sync the "
            "artifact repo by running make in the artifact directory." % name)
      return result