code: def _enclose_readings(container, readings):
      
      container_start, container_end = tuple(container)
      enclosed_readings = '%(container_start)s%(readings)s%(container_end)s' % {
          'container_start': container_start, 'container_end': container_end,
          'readings': readings}
      return enclosed_readings
docs: Enclose a reading within a container, e.g. '[]'.