# File lib/hammer_cli/completer.rb, line 157
    def option_to_complete(cmd, line)
      return [nil, nil] if line.empty?

      if line.complete?
        # last word must be option and can't be flag -> we complete the value
        # "--option " or "--option xx "
        opt = find_option(cmd, line[-1])
        return [opt, nil] if opt and not opt.flag?
      else
        # we complete the value in the second case
        # "--opt" or "--option xx" or "xx yy"
        opt = find_option(cmd, line[-2])
        return [opt, line[-1]] if opt and not opt.flag?
      end
      return [nil, nil]
    end