docs: def hosts_append(hostsfile='/etc/hosts', ip_addr=None, entries=None):
      '''
      Append a single line to the /etc/hosts file.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' dnsutil.hosts_append /etc/hosts 127.0.0.1 ad1.yuk.co,ad2.yuk.co
      '''
      host_list = entries.split(',')
      hosts = parse_hosts(hostsfile=hostsfile)
      if ip_addr in hosts:
          for host in host_list:
              if host in hosts[ip_addr]:
                  host_list.remove(host)
  
      if not host_list:
          return 'No additional hosts were added to {0}'.format(hostsfile)
  
      append_line = '\n{0} {1}'.format(ip_addr, ' '.join(host_list))
      with salt.utils.files.fopen(hostsfile, 'a') as fp_:
          fp_.write(salt.utils.stringutils.to_str(append_line))
  
      return 'The following line was added to {0}:{1}'.format(hostsfile,
                                                              append_line)