AssertionError complete_scan.py

[raspberryananas]

Traceback (most recent call last):
File "complete_scan.py", line 394, in
tf.app.run(main)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/platform/app.py", line 125, in run
_sys.exit(main(argv))
File "complete_scan.py", line 300, in main
FLAGS.num_quant_levels, FLAGS.p_norm, FLAGS.predict_semantics)
File "complete_scan.py", line 128, in read_inputs
assert os.path.isfile(previous_file)
AssertionError

In complete_scan.py line 122:

if not FLAGS.is_base_level:
previous_file = os.path.join(
FLAGS.output_dir_prev, 'level' + str(FLAGS.hierarchy_level - 1) + '_' +
os.path.splitext(os.path.basename(filename))[0] + 'pred.tfrecord')
tf.logging.info('Reading previous predictions frome file: %s',
previous_file)
assert os.path.isfile(previous_file)

Any ideas?