NSRange range = NSMakeRange(start, end-start);
[self willChange:NSKeyValueChangeInsertion valuesAtIndexes:[NSIndexSet indexSetWithIndexesInRange:range] forKey:@"media"];
[self willChange:NSKeyValueChangeInsertion valuesAtIndexes:[NSIndexSet indexSetWithIndexesInRange:range] forKey:@"node"];
for( NSDictionary * args in arrayOfArgs )
{
NSRange range = NSMakeRange(start, end-start);
[self willChange:NSKeyValueChangeInsertion valuesAtIndexes:[NSIndexSet indexSetWithIndexesInRange:range] forKey:@"media"];
[self willChange:NSKeyValueChangeInsertion valuesAtIndexes:[NSIndexSet indexSetWithIndexesInRange:range] forKey:@"node"];
for( NSDictionary * args in arrayOfArgs )
{