def GetMissingOwnerErrors(metrics):
  """Check that all of the metrics have owners.

  Args:
    metrics: A list of rappor metric description objects.

  Returns:
    A list of errors about metrics missing owners.
  """
  missing_owners = [m for m in metrics if not m['owners']]
  return ['Rappor metric "%s" is missing an owner.' % metric['name']
          for metric in missing_owners]