diff --git a/fsql/deser.py b/fsql/deser.py
index a06dfdc..327622d 100644
--- a/fsql/deser.py
+++ b/fsql/deser.py
@@ -53,7 +53,7 @@
 from enum import Enum, auto, unique
 from functools import partial, reduce
 from itertools import chain
-from typing import Any, Generic, Iterable, NamedTuple, Tuple, TypeVar, Union
+from typing import Any, Generic, Iterable, Tuple, TypeVar, Union
 
 import pandas as pd
 from fsspec.core import OpenFile
@@ -98,12 +98,14 @@ def from_url(cls, url: str):
 DataObject = TypeVar("DataObject")
 
 
-class DataObjectRich(NamedTuple, Generic[DataObject]):
+@dataclass(frozen=True)
+class DataObjectRich(Generic[DataObject]):
     data: DataObject
     failures: Iterable[PartitionReadFailure]
 
 
-class PartitionReadFailure(NamedTuple):
+@dataclass(frozen=True)
+class PartitionReadFailure:
     partition: Partition
     reason: str  # or Any?
 
diff --git a/tests/test_dict_reader.py b/tests/test_dict_reader.py
index 00012e7..da4679e 100644
--- a/tests/test_dict_reader.py
+++ b/tests/test_dict_reader.py
@@ -39,5 +39,5 @@ def test_lazy_errors(tmp_path):
 
     lazy_reader = EnumeratedDictReader(lazy_errors=True)
     result = read_partitioned_table(f"file://{case1_path}/", Q_TRUE, data_reader=lazy_reader)
-    assert result[0] == {0: json.loads(data1)}
-    assert [error_line] == [e.reason for e in result[1]]
+    assert result.data == {0: json.loads(data1)}
+    assert [error_line] == [e.reason for e in result.failures]
diff --git a/tests/test_pandasreader.py b/tests/test_pandasreader.py
index e6e3d1f..ec798eb 100644
--- a/tests/test_pandasreader.py
+++ b/tests/test_pandasreader.py
@@ -51,6 +51,6 @@ def test_lazy_errors(tmp_path):
         result = read_partitioned_table(f"file://{case1_path}/", Q_TRUE, data_reader=reader_eager)
     reader_lazy = PandasReader(columns=["c3"], lazy_errors=True)
     result = read_partitioned_table(f"file://{case1_path}/", Q_TRUE, data_reader=reader_lazy)
-    assert_frame_equal(df2[["c3"]], result[0])
-    reasons = [e.reason.split("\n")[0] for e in result[1]]
+    assert_frame_equal(df2[["c3"]], result.data)
+    reasons = [e.reason.split("\n")[0] for e in result.failures]
     assert reasons == [error_line]