def add_itemprop(itemprop)
      properties = Itemprop.parse(itemprop, @page_url)
      properties.each { |name, value| (@properties[name] ||= []) << value }
    end
def add_itemprop(itemprop)
      properties = Itemprop.parse(itemprop, @page_url)
      properties.each { |name, value| (@properties[name] ||= []) << value }
    end
Add an 'itemprop' to the properties