triggerSample

 trigger ContactTrigger on Contact (after delete, after insert, after undelete, 
                                    after update, before delete, before insert, before update) {
    if(trigger.isAfter && trigger.isInsert){
         Map<String,List<Contact>> mapIdByList=ParentChildMapHelper.buildGeneralisedMap('AccountId',trigger.new);
         system.debug(mapIdByList);
    }
    
}