def _combined_model_name(org, repo=None):
  """Return the name of the combined model for a repo or organization.

  If repo is specified looks for a repo specific model. If repo is
  none we return an org wide model.

  Args:
    org: Name of the org.
    repo: (Optional) The name of the repo
  """
  if repo:
    return f"{org}/{repo}_combined"

  return f"{org}_combined"