code: function(aggregate, vm, callback) {
                  if(aggregate.get('destroyed')) {
                      var reason = {
                          name: 'AggregateDestroyed',
                          message: 'Aggregate has already been destroyed!',
                          aggregateRevision: aggregate.get('revision'),
                          aggregateId: aggregate.id
                      };
                      return callback(reason);
                  }
                  
                  callback(null, aggregate, vm);
              }
docs: reject command if aggregate has already been destroyed