def method_missing(name, *args, &block)
      if args.empty? && !block_given?
        if @params.key?(name)
          return @params[name]
        else
          active_params.each do |param|
            return param.send(name) if param.respond_to_missing?(name)
          end
        end
      end

      super
    end
def method_missing(name, *args, &block)
      if args.empty? && !block_given?
        if @params.key?(name)
          return @params[name]
        else
          active_params.each do |param|
            return param.send(name) if param.respond_to_missing?(name)
          end
        end
      end

      super
    end
If a parameter with the specified method name exists, a call to that
 method will return the value of the parameter.

 @param (see ClassMethods#method_missing)

 @example
   option :user, [:who]
   command :hello, [:mood] do
     puts "Hello #{user.who}"
     puts "I feel #{mood}"
   end