Not possible to sort TimeStampedModel by modified

[xi]

TimeStampedModel.modified is None if the item has never been modified. This makes sense, especially considering UI where edited items get an additional "this has been edited on …" label.

However, this makes it impossible to sort by "recent changes". It might be better to set both modified and created on creation. To know weather an item has been edited you would then check for equality of these fields.