public Map<List<String>, String> extractNestedDrivers(XTrace trace) {
		return XCostDriver.instance().extractNestedValues(trace);
	}
public Map < List < String > , String > extractNestedDrivers ( XTrace trace ) { return XCostDriver . instance ( ) . extractNestedValues ( trace ) ; }
Retrieves a map containing all cost drivers for all descending attributes
of a trace.

@see #extractNestedAmounts(XTrace)

@param trace
Trace to retrieve all cost drivers for.
@return Map from all descending keys to cost drivers.