add serializable

Author: arrjon

tests/test_networks/conftest.py

@@ -1,9 +1,8 @@
 import pytest
 
-from bayesflow.networks import MLP
+from bayesflow.networks import MLP, Sequential
 from bayesflow.utils.tensor_utils import concatenate_valid
 from bayesflow.utils.serialization import serializable
-import keras
 
 
 @pytest.fixture()
@@ -19,7 +18,7 @@ def diffusion_model_edm_F():
 
 
 @serializable("bayesflow.networks")
-class ConcatenateMLP(keras.Layer):
+class ConcatenateMLP(Sequential):
     def __init__(self, widths):
         super().__init__()
         self.widths = widths