Compute the values for single valued aggregations

        :returns: the single aggregation value

def get_aggs(self):
        """
        Compute the values for single valued aggregations

        :returns: the single aggregation value
        """

        res = self.fetch_aggregation_results()
        if 'aggregations' in res and 'values' in res['aggregations'][str(self.parent_agg_counter - 1)]:
            try:
                agg = res['aggregations'][str(self.parent_agg_counter - 1)]['values']["50.0"]
                if agg == 'NaN':
                    # ES returns NaN. Convert to None for matplotlib graph
                    agg = None
            except Exception as e:
                raise RuntimeError("Multivalue aggregation result not supported")

        elif 'aggregations' in res and 'value' in res['aggregations'][str(self.parent_agg_counter - 1)]:
            agg = res['aggregations'][str(self.parent_agg_counter - 1)]['value']

        else:
            agg = res['hits']['total']

        return agg