ketos pretrain fails with AttributeError

[fusselheber]

With kraken 5.2.9 and 5.3.0: On the command-line, run
> ketos pretrain -f page page.xml
where page.xml is a valid Page XML file of your choice. This fails with error
AttributeError: 'AttributeDict' object has no attribute 'hyper_params'
The same error occurs when using multiple XML files or a binary.

The following edit fixed my kraken 5.2.9 installation: in kraken/lib/progress.py, replace line 136
f"{self.trainer.max_epochs if self.trainer.model.hparams.hyper_params['quit'] == 'fixed' else '∞'}"
by
f"{self.trainer.max_epochs if self.trainer.model.hparams['quit'] == 'fixed' else '∞'}"