diff --git a/icechunk-python/benchmarks/test_benchmark_reads.py b/icechunk-python/benchmarks/test_benchmark_reads.py
index d1f488ce..b1ba9e6e 100644
--- a/icechunk-python/benchmarks/test_benchmark_reads.py
+++ b/icechunk-python/benchmarks/test_benchmark_reads.py
@@ -48,7 +48,11 @@ def test_time_getsize_key(synth_dataset: Dataset, benchmark) -> None:
     @benchmark
     def fn():
         for array in synth_dataset.load_variables:
-            key = f"{synth_dataset.group or ''}/{array}/zarr.json"
+            if group := synth_dataset.group is not None:
+                prefix = f"{group}/"
+            else:
+                prefix = ""
+            key = f"{prefix}{array}/zarr.json"
             sync(store.getsize(key))