def parse(node)
      node.attributes.each do |key, value|
        case key
        when 'algn', 'val'
          @value = value_to_symbol(value)
        when 'leader'
          @leader = value_to_symbol(value)
        when 'pos'
          @position = OoxmlSize.new(value.value.to_f, position_unit(node))
        end
      end
      self
    end
def parse(node)
      node.attributes.each do |key, value|
        case key
        when 'algn', 'val'
          @value = value_to_symbol(value)
        when 'leader'
          @leader = value_to_symbol(value)
        when 'pos'
          @position = OoxmlSize.new(value.value.to_f, position_unit(node))
        end
      end
      self
    end
Parse ParagraphTab object
 @param node [Nokogiri::XML:Element] node to parse
 @return [ParagraphTab] result of parsing