def parse(node)
      node.xpath('*').each do |column_node|
        case column_node.name
        when 'ext'
          @extension_array << Extension.new(parent: self).parse(column_node)
        end
      end
      self
    end
def parse(node)
      node.xpath('*').each do |column_node|
        case column_node.name
        when 'ext'
          @extension_array << Extension.new(parent: self).parse(column_node)
        end
      end
      self
    end
Parse ExtensionList data
 @param [Nokogiri::XML:Element] node with ExtensionList data
 @return [ExtensionList] value of ExtensionList data