Resolve "lr_decay should be optional"

Closes #71 (closed)

src/run_modules/model_setup.py

@@ -70,11 +70,12 @@ class ModelSetup(RunEnvironment):
         Set all callbacks for the training phase. Add all callbacks with the .add_callback statement. Finally, the
         advanced model checkpoint is added.
         """
-        lr = self.data_store.get("lr_decay", scope="general.model")
+        lr = self.data_store.get_default("lr_decay", scope="general.model", default=None)
         hist = HistoryAdvanced()
         self.data_store.set("hist", hist, scope="general.model")
         callbacks = CallbackHandler()
-        callbacks.add_callback(lr, self.callbacks_name % "lr", "lr")
+        if lr:
+            callbacks.add_callback(lr, self.callbacks_name % "lr", "lr")
         callbacks.add_callback(hist, self.callbacks_name % "hist", "hist")
         callbacks.create_model_checkpoint(filepath=self.checkpoint_name, verbose=1, monitor='val_loss',
                                           save_best_only=True, mode='auto')