def parse(node)
      node.xpath('*').each do |child_node|
        case child_node.name
        when 'legendPos'
          @position = value_to_symbol(child_node.attribute('val'))
        when 'overlay'
          @overlay = true if child_node.attribute('val').value.to_s == '1'
        end
      end
      self
    end
def parse(node)
      node.xpath('*').each do |child_node|
        case child_node.name
        when 'legendPos'
          @position = value_to_symbol(child_node.attribute('val'))
        when 'overlay'
          @overlay = true if child_node.attribute('val').value.to_s == '1'
        end
      end
      self
    end
Parse ChartLegend object
 @param node [Nokogiri::XML:Element] node to parse
 @return [ChartLegend] result of parsing