def parse_symbol attr_name, xpath
      v = parse_value xpath
      v = v.to_sym unless v.nil?
      send("#{attr_name}=", v)
    end
def parse_symbol attr_name, xpath
      v = parse_value xpath
      v = v.to_sym unless v.nil?
      send("#{attr_name}=", v)
    end
parse convert and assign node text to symbol