diff --git a/jinete/loaders/file.py b/jinete/loaders/file.py
index 29590172..a4265d67 100644
--- a/jinete/loaders/file.py
+++ b/jinete/loaders/file.py
@@ -43,7 +43,7 @@ def __init__(self, file_path: Path, *args, **kwargs):
     @property
     def data(self):
         with self.file_path.open() as file:
-            data = tuple(tuple(float(v) for v in line.split()) for line in file.readlines())
+            data = list(list(float(v) for v in line.split()) for line in file.readlines())
         return data
 
     @property
diff --git a/tests/test_loaders/test_file.py b/tests/test_loaders/test_file.py
index f0514fde..fe5dbe1b 100644
--- a/tests/test_loaders/test_file.py
+++ b/tests/test_loaders/test_file.py
@@ -8,25 +8,25 @@
 
 if TYPE_CHECKING:
     from typing import (
-        Tuple,
+        Sequence
     )
 
 
 class TestFileLoader(unittest.TestCase):
     directory_path: Path
     file_path: Path
-    data: Tuple[Tuple[float, ...], ...]
+    data: Sequence[Sequence[float]]
 
     @classmethod
     def setUpClass(cls) -> None:
         cls.directory_path = Path('/tmp/')
         cls.file_path = cls.directory_path / 'jinete_problem_test.txt'
-        cls.data = (
-            (1.0, 1, 480, 6.0, 90.0),
-            (0.0, -1.044, 2.000, 0.0, 0.0, 0.0, 1440.0),
-            (1.0, -2.973, 6.414, 10.0, 1.0, 0.0, 1440.0),
-            (2.0, -5.476, 1.437, 10.0, -1.0, 258.0, 287.0),
-        )
+        cls.data = [
+            [1.0, 1, 480, 6.0, 90.0],
+            [0.0, -1.044, 2.000, 0.0, 0.0, 0.0, 1440.0],
+            [1.0, -2.973, 6.414, 10.0, 1.0, 0.0, 1440.0],
+            [2.0, -5.476, 1.437, 10.0, -1.0, 258.0, 287.0],
+        ]
         with cls.file_path.open('w') as file:
             file.writelines('\t'.join(str(cell) for cell in row) + '\n' for row in cls.data)