_vos_storage()
{
  local cur prev opts
  COMPREPLY=()
  cur="${COMP_WORDS[COMP_CWORD]}"
  prev="${COMP_WORDS[COMP_CWORD-1]}"
  opts="add del list"

  if [[ ${cur} == add || ${cur} == del || ${cur} == list || ${COMP_CWORD} -eq 1 ]] ; then
    COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
    return 0
  fi
}
complete -F _vos_storage vos_storage
