Finetuning the recognizer crashes when reaching the fit_generator method

[jnluca]

Hi, the code provided to finetune the recognizer is not working anymore. When I open your example keras_ocr_born_digital_public.ipynb on Colab and run it, the fit_generator method crashes with the following message:

Epoch 1/1000

ValueError Traceback (most recent call last)
in <cell line: 1>()
----> 1 recognizer.training_model.fit(
2 final_train_gen(training_gen),
3 batch_size=1,
4 steps_per_epoch=training_steps,
5 validation_steps=validation_steps,

1 frames
/usr/local/lib/python3.10/dist-packages/keras/engine/training.py in tf__train_function(iterator)
13 try:
14 do_return = True
---> 15 retval_ = ag__.converted_call(ag__.ld(step_function), (ag__.ld(self), ag__.ld(iterator)), None, fscope)
16 except:
17 do_return = False

ValueError: in user code:

File "/usr/local/lib/python3.10/dist-packages/keras/engine/training.py", line 1284, in train_function  *
    return step_function(self, iterator)
File "/usr/local/lib/python3.10/dist-packages/keras/engine/training.py", line 1268, in step_function  **
    outputs = model.distribute_strategy.run(run_step, args=(data,))
File "/usr/local/lib/python3.10/dist-packages/keras/engine/training.py", line 1249, in run_step  **
    outputs = model.train_step(data)
File "/usr/local/lib/python3.10/dist-packages/keras/engine/training.py", line 1050, in train_step
    y_pred = self(x, training=True)
File "/usr/local/lib/python3.10/dist-packages/keras/utils/traceback_utils.py", line 70, in error_handler
    raise e.with_traceback(filtered_tb) from None

ValueError: Exception encountered when calling layer 'lambda_1' (type Lambda).

None values not supported.

Call arguments received by layer 'lambda_1' (type Lambda):
  • inputs=['tf.Tensor(shape=(None, None, None, 512), dtype=float32)', 'tf.Tensor(shape=(None, 6), dtype=float32)']
  • mask=None
  • training=True