def each
      @data.each do |section, hash|
        hash.each do |key, value|
          yield [section, key, value]
        end
      end
    end
def each
      @data.each do |section, hash|
        hash.each do |key, value|
          yield [section, key, value]
        end
      end
    end
For a block.

 Receive the section and its pairs for the current configuration.

   config.each do |section, key, value|
     # ...
   end