docs: def policy_error_scope(error, data):
      """Scope a schema error to its policy name and resource."""
      err_path = list(error.absolute_path)
      if err_path[0] != 'policies':
          return error
      pdata = data['policies'][err_path[1]]
      pdata.get('name', 'unknown')
      error.message = "Error on policy:{} resource:{}\n".format(
          pdata.get('name', 'unknown'), pdata.get('resource', 'unknown')) + error.message
      return error