Fix duplicated inputs bug in MarginalizedRV construction

Author: ricardoV94

pymc_experimental/model/marginal_model.py

@@ -683,7 +683,7 @@ def replace_finite_discrete_marginal_subgraph(fgraph, rv_to_marginalize, all_rvs
                 "This is currently not supported",
             )
 
-    input_rvs = [*marginalized_rv_input_rvs, *dependent_rvs_input_rvs]
+    input_rvs = list(set((*marginalized_rv_input_rvs, *dependent_rvs_input_rvs)))
     rvs_to_marginalize = [rv_to_marginalize, *dependent_rvs]
 
     outputs = rvs_to_marginalize

tests/model/test_marginal_model.py

@@ -754,7 +754,6 @@ def test_batched(self):
         assert post.idx.shape == post.y.shape
         assert post.lp_idx.shape == (*post.idx.shape, 2)
 
-    @pytest.mark.xfail(reason="Still need to investigate")
     def test_nested(self):
         """Test that marginalization works when there are nested marginalized RVs"""