def parse(node)
      node.xpath('*').each do |node_child|
        case node_child.name
        when 't'
          @text = node_child.text
        when 'r'
          @run = ParagraphRun.new(parent: self).parse(node_child)
        end
      end
      self
    end
def parse(node)
      node.xpath('*').each do |node_child|
        case node_child.name
        when 't'
          @text = node_child.text
        when 'r'
          @run = ParagraphRun.new(parent: self).parse(node_child)
        end
      end
      self
    end
Parse StringIndex data
 @param [Nokogiri::XML:Element] node with StringIndex data
 @return [StringIndex] value of StringIndex data