lib/opt_parse_validator/opts/multi_choices.rb
def opt_help_messages(opt)
      opt.help_messages.empty? ? [opt.to_s.humanize] : opt.help_messages
    end
def opt_help_messages(opt)
      opt.help_messages.empty? ? [opt.to_s.humanize] : opt.help_messages
    end
@param [ OptBase ] opt

 @return [ Array<String> ]