set default value for pretrained_model to None

experiments/experiment_midlevel.py

@@ -175,7 +175,7 @@ if __name__=='__main__':
     parent_parser.add_argument('--train_percent', type=float,
                                default=1.0, help='how much train data to use')
     parent_parser.add_argument('--pretrained_midlevel',
-                               default="/home/verena/experiments/moodwalk/runs/ca601 - pretrain_midlevel 20 epochs/midlevel.ckpt/", type=str)
+                               default=None, type=str)
     parser = Network.add_model_specific_args(parent_parser)
     hyperparams = parser.parse_args()
     run(hyperparams)
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