code: def test_namedtuple():
      a = ProvenanceTensor(torch.randn(3, 3), frozenset({"a"}))
      b = ProvenanceTensor(torch.randn(3, 3), frozenset({"b"}))
      result = torch.linalg.solve_triangular(b, a, upper=True)
      actual = getattr(result, "_provenance", frozenset())
      assert actual == frozenset({"a", "b"})
  
file_path: funsor/test/torch/test_provenance.py
imports: import pytest
  import torch
  from pyro.ops.indexing import Vindex
  from funsor.torch.provenance import ProvenanceTensor
label_desc: Use image node_id 5 for calling a global function with example usage: test_namedtuple() without return types