def METHOD_NAME(iam, project_id, service_account_id):
  """Try to get a service account. Returns None if it does not exist."""
  try:
    request = iam.projects().serviceAccounts().get(
        name='projects/{0}/serviceAccounts/{1}'.format(
            project_id, _service_account_email(project_id, service_account_id)))
    return request.execute()
  except googleapiclient.errors.HttpError as e:
    if e.resp.status == 404:
      return None
    raise