docs: def checkIsReachable(rh):
      """
      Check if a virtual machine is reachable.
  
      Input:
         Request Handle with the following properties:
            function    - 'POWERVM'
            subfunction - 'ISREACHABLE'
            userid      - userid of the virtual machine
  
      Output:
         Request Handle updated with the results.
         overallRC - 0: determined the status, non-zero: some weird failure
                                               while trying to execute a command
                                               on the guest via IUCV
         rc - RC returned from execCmdThruIUCV
         rs - 0: not reachable, 1: reachable
      """
  
      rh.printSysLog("Enter powerVM.checkIsReachable, userid: " +
          rh.userid)
  
      strCmd = "echo 'ping'"
      results = execCmdThruIUCV(rh, rh.userid, strCmd)
  
      if results['overallRC'] == 0:
          rh.printLn("N", rh.userid + ": reachable")
          reachable = 1
      else:
          # A failure from execCmdThruIUCV is acceptable way of determining
          # that the system is unreachable.  We won't pass along the
          # error message.
          rh.printLn("N", rh.userid + ": unreachable")
          reachable = 0
  
      rh.updateResults({"rs": reachable})
      rh.printSysLog("Exit powerVM.checkIsReachable, rc: 0")
      return 0