def call
      if arguments.valid?
        Qiita::Commands::Request.new(arguments)
      else
        Qiita::Commands::Error.new(arguments)
      end
    end
def call
      if arguments.valid?
        Qiita::Commands::Request.new(arguments)
      else
        Qiita::Commands::Error.new(arguments)
      end
    end
Qiita::CommandBuilder.new(argv)
 Creates a new instance of Qiita::CommandBuilder from given command line arguments.

 Qiita::CommandBuilder#call
 Returns a new instance of command class that inherited from Qiita::Commands::Base.