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

@@ -373,7 +373,6 @@ def test_recover_batched_marginal():
     assert post.lp_idx.shape == (*post.idx.shape, 2)
 
 
-@pytest.mark.xfail(reason="Still need to investigate")
 def test_nested_recover_marginals():
     """Test that marginalization works when there are nested marginalized RVs"""