diff --git a/stan/tests/test_stan_functions.py b/stan/tests/test_stan_functions.py
index 2243d3c..b0182c2 100644
--- a/stan/tests/test_stan_functions.py
+++ b/stan/tests/test_stan_functions.py
@@ -91,7 +91,7 @@ def assert_stan_function_allclose(
         return
     # Verify against expected value. We only check one because we have already verified that they
     # are the same.
-    result, = fit.stan_variable("result")
+    result = fit.stan_variable("result")[0]
     if not isinstance(desired, list):
         desired = [desired]
     try: