'Called when an epoch is about to end
Arguments:
callback_data (HDF5 dataset): shared data between callbacks
model (Model): model object
epoch (int): index of epoch that is ending'

def on_epoch_end(self, callback_data, model, epoch):

    _eil = self._get_cached_epoch_loss(callback_data, model, epoch, 'loss')
    if _eil:
        progress_string = ('    [%s    %.2f,    %.2fs]' % (_eil['costnm'], _eil['cost'], _eil['time']))
        sys.stdout.write(progress_string)
        sys.stdout.flush()
    sys.stdout.write('\n')
