Fix extension test for Keras v3

Author: vloncar

docs/advanced/extension.rst

@@ -35,6 +35,10 @@ For concreteness, let's say our custom layer ``KReverse`` is implemented in Kera
         def call(self, inputs):
             return tf.reverse(inputs, axis=[-1])
 
+        def get_config(self):
+            return super().get_config()
+
+Make sure you define a ``get_config()`` method for your custom layer as this is needed for correct parsing.
 We can define the equivalent layer in hls4ml ``HReverse``, which inherits from ``hls4ml.model.layers.Layer``.
 
 .. code-block:: Python

test/pytest/test_extensions.py

@@ -19,6 +19,10 @@ def __init__(self):
     def call(self, inputs):
         return tf.reverse(inputs, axis=[-1])
 
+    def get_config(self):
+        # Breaks serialization and parsing in hls4ml if not defined
+        return super().get_config()
+
 
 # hls4ml layer implementation
 class HReverse(hls4ml.model.layers.Layer):