diff --git a/python/tests/test_ADMDatamart.py b/python/tests/test_ADMDatamart.py
index 8ff48ac0..3a3b261b 100644
--- a/python/tests/test_ADMDatamart.py
+++ b/python/tests/test_ADMDatamart.py
@@ -28,7 +28,7 @@ class Shape:
     """
 
     def __new__(cls, ldf: pl.LazyFrame):
-        return (ldf.select(pl.first().count()).collect().item(), len(ldf.columns))
+        return (ldf.select(pl.first().len()).collect().item(), len(ldf.columns))
 
 
 @pl.api.register_lazyframe_namespace("frame")
diff --git a/python/tests/test_IO.py b/python/tests/test_IO.py
index b95e4cd3..08e26abc 100644
--- a/python/tests/test_IO.py
+++ b/python/tests/test_IO.py
@@ -29,7 +29,7 @@ class Shape:
     """
 
     def __new__(cls, ldf: pl.LazyFrame):
-        return (ldf.select(pl.first().count()).collect().item(), len(ldf.columns))
+        return (ldf.select(pl.first().len()).collect().item(), len(ldf.columns))
 
 
 @pytest.fixture
diff --git a/python/tests/test_datasets.py b/python/tests/test_datasets.py
index 48f7d475..47f641f1 100644
--- a/python/tests/test_datasets.py
+++ b/python/tests/test_datasets.py
@@ -19,7 +19,7 @@ class Shape:
     """
 
     def __new__(cls, ldf: pl.LazyFrame):
-        return (ldf.select(pl.first().count()).collect().item(), len(ldf.columns))
+        return (ldf.select(pl.first().len()).collect().item(), len(ldf.columns))
 
 
 def test_import_CDHSample():
diff --git a/python/tests/test_end_to_end.py b/python/tests/test_end_to_end.py
index 54e1a70f..eaefa30e 100644
--- a/python/tests/test_end_to_end.py
+++ b/python/tests/test_end_to_end.py
@@ -3,6 +3,7 @@
 """
 import sys
 import pathlib
+
 basePath = pathlib.Path(__file__).parent.parent.parent
 sys.path.append(f"{str(basePath)}/python")
 import polars as pl
@@ -20,7 +21,7 @@ class Shape:
     """
 
     def __new__(cls, ldf: pl.LazyFrame):
-        return (ldf.select(pl.first().count()).collect().item(), len(ldf.columns))
+        return (ldf.select(pl.first().len()).collect().item(), len(ldf.columns))
 
 
 def test_end_to_end():
@@ -65,7 +66,7 @@ def test_end_to_end():
         "BinAdjustedPropensity",
         "Contents",
         "PredictorCategory",
-        "GroupIndex"
+        "GroupIndex",
     }
     assert set(datamart.predictorData.columns) == predcols
 
@@ -90,7 +91,7 @@ def test_end_to_end():
         "EntryType",
         "BinNegatives",
         "Contents",
-        "GroupIndex"
+        "GroupIndex",
     }
 
     assert datamart.missing_preds == {
@@ -134,7 +135,7 @@ def test_end_to_end():
         "BinResponseCount",
         "PredictorName",
         "Contents",
-        "GroupIndex"
+        "GroupIndex",
     }
 
     assert isinstance(datamart.plotPerformanceSuccessRateBubbleChart(), Figure)