def get_summary_data(self, group_name):
        """ Get the summary data for an analysis group.
        
        :param group_name: The name of the analysis group to pull summary
            data for.
        :returns: A dictionary whose keys are analysis steps, and whose
            values are dictionaries of key/value pairs for the results of
            that step.
        """
        self.assert_open()
        group = 'Analyses/{}/Summary'.format(group_name)
        summary = None
        if group in self.handle:
            summary = self._parse_attribute_tree(group)
        return summary
Get the summary data for an analysis group.
        
        :param group_name: The name of the analysis group to pull summary
            data for.
        :returns: A dictionary whose keys are analysis steps, and whose
            values are dictionaries of key/value pairs for the results of
            that step.