code: def _error_msg_routes(iface, option, expected):
      '''
      Build an appropriate error message from a given option and
      a list of expected values.
      '''
      msg = 'Invalid option -- Route interface: {0}, Option: {1}, Expected: [{2}]'
      return msg.format(iface, option, expectedf _error_msg_routes(iface, option, expected):
      '''
      Build an appropriate error message from a given option and
      a list of expected values.
      '''
      msg = 'Invalid option -- Route interface: {0}, Option: {1}, Expected: [{2}]'
      return msg.format(iface, option, expected)
docs: Build an appropriate error message from a given option and
      a list of expected values.