uncommented imports that were commented for testing in model_class.py and...

uncommented imports that were commented for testing in model_class.py and fixed InputSpec import in advanced_paddings.py

mlair/model_modules/advanced_paddings.py

@@ -8,7 +8,6 @@ from typing import Union, Tuple
 
 import numpy as np
 import tensorflow as tf
-from tensorflow.keras import backend as K
 # from tensorflow.keras.backend.common import normalize_data_format
 from tensorflow.keras.layers import ZeroPadding2D
 # from tensorflow.keras.layers.convolutional import _ZeroPadding
@@ -257,7 +256,7 @@ class _ZeroPadding(Layer):
         # self.rank is 1 for ZeroPadding1D, 2 for ZeroPadding2D.
         self.rank = len(padding)
         self.padding = padding
-        self.data_format = K.normalize_data_format(data_format)
+        self.data_format = normalize_data_format(data_format)
         self.input_spec = InputSpec(ndim=self.rank + 2)
         super(_ZeroPadding, self).__init__(**kwargs)