code: def walk_snmp_values(sess, helper, oid, check):
          
          try:
              snmp_walk = sess.walk_oid(oid)
  
              result_list = []
              for x in range(len(snmp_walk)):
                  result_list.append(snmp_walk[x].val)
  
              if result_list != []:
                  return result_list
  
              else:
                  raise SnmpException("No content")
          except SnmpException:
              helper.exit(summary="No response from device for {} ({})".format(check, oid),
                          exit_code=unknown, perfdata='')
docs: return a snmp value or exits the plugin with unknown