docs: def MX(domain, resolve=False, nameserver=None):
      '''
      Return a list of lists for the MX of ``domain``.
  
      If the 'resolve' argument is True, resolve IPs for the servers.
  
      It's limited to one IP, because although in practice it's very rarely a
      round robin, it is an acceptable configuration and pulling just one IP lets
      the data be similar to the non-resolved version. If you think an MX has
      multiple IPs, don't use the resolver here, resolve them in a separate step.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt ns1 dnsutil.MX google.com
      '''
      if _has_dig():
          return __salt__['dig.MX'](domain, resolve, nameserver)
  
      return 'This function requires dig, which is not currently available'