private void buildCalculationMethodCombinationTree(string compoundName, CalculationMethodCache configurationCache, TreeItem <CalculationMethodWithCompoundName> treeRoot)
{
var categoryCache = new Cache <string, IEnumerable <CalculationMethodWithCompoundName> >();
configurationCache.GroupBy(method => method.Category).Each(grouping =>
{
categoryCache[grouping.Key] = grouping.Select(method => new CalculationMethodWithCompoundName(method, compoundName)).ToList();
});
categoryCache.Keys.Each(key => treeRoot.AddToAllLeaves(categoryCache[key]));
}