Failed to train UNET

Hi, adjust UNET structure for 4 depth, instead of 3 depth, and training show an error, for weight names, can you give me the sign how to adjust original coding part? I did not find the part for this error shown

ValueError Traceback (most recent call last)
in <cell line: 18>()
16 start = time.time()
17 # Start Training
---> 18 model.train(epochs=number_of_epochs,
19 batch_size=batch_size,
20 train_generator=train_generator,

1 frames
/usr/local/lib/python3.10/dist-packages/keras/src/callbacks/model_checkpoint.py in init(self, filepath, monitor, verbose, save_best_only, save_weights_only, mode, save_freq, initial_value_threshold)
181 if save_weights_only:
182 if not self.filepath.endswith(".weights.h5"):
--> 183 raise ValueError(
184 "When using save_weights_only=True in ModelCheckpoint"
185 ", the filepath provided must end in .weights.h5 "

ValueError: When using save_weights_only=True in ModelCheckpoint, the filepath provided must end in .weights.h5 (Keras weights format). Received: filepath=/content/gdrive/MyDrive/cryo/cryo-data_processing_volume/model/gaussian4layer_320_50_0.00014/ckpt/gaussian4layer_320_50_0.00014.hdf5

Start at the notebook cell calling model.train and inspect the ModelCheckpoint setup shown in the traceback. Confirm how the checkpoint filepath is constructed and how the UNET depth is configured. Done means the requested four-depth configuration is understood and training reaches checkpoint creation without the filepath error.