How to use the ecl.summary.ecl_sum_node.EclSumNode function in ecl

def __iget(self, index):
        """
        Will return an EclSumNode for element @index; should be called
        through the [] operator, otherwise you can come across
        unitialized data.
        """
        return EclSumNode(self.__report_step[index],
                          self.__days[index],
                          self.__dates[index],
                          self.__mpl_dates[index],
                          self.__values[index])

def __iget(self, index):
        """
        Will return an EclSumNode for element @index; should be called
        through the [] operator, otherwise you can come across
        unitialized data.
        """
        return EclSumNode(self.__report_step[index],
                          self.__days[index],
                          self.__dates[index],
                          self.mpl_dates[index],
                          self.__values[index])