revert removal of prior_model: null in ANI-2x config file as it causes too many test failures

Author: stefdoerr

examples/TensorNet-ANI2X.yaml

@@ -39,6 +39,7 @@ num_rbf: 32
 num_workers: 4
 output_model: Scalar
 precision: 32
+prior_model: null
 remove_ref_energy: true
 rbf_type: expnorm
 redirect: false

tests/test_examples.py

@@ -19,7 +19,7 @@ def test_example_yamls(fname):
         args = yaml.load(f, Loader=yaml.FullLoader)
 
     prior = None
-    if "prior_model" in args and args["prior_model"] is not None:
+    if args["prior_model"] is not None:
         dataset = DummyDataset(has_atomref=True)
         prior = getattr(priors, args["prior_model"])(dataset=dataset)