New way of creating a map from recently inserted records

getidofRecords.txt

//After Inserting opportunities
List<Opportunity> opptys = new List<Opportunity>();
insert opptys;

// Get the IDs of the opportunities we just inserted
Map<Id, Opportunity> opptyMap = new Map<Id, Opportunity>(opptys);
//This will create a map of the opportunities
// Will allow you to do this
List<Id> opptyIds = new List<Id>(opptyMap.keySet());