public static AggregateDictionary GetAggregationContainingResult <T>(this AggregateDictionary aggs,
Expression <Func <T, object> > filterRule = null)
{
if (filterRule == null)
{
return(aggs);
}
var filterName = filterRule.GenerateFilterName();
aggs.CheckForAggregationInResult(filterName);
return(aggs.Filter(filterName));
}