diff --git a/setup.cfg b/setup.cfg
index 916c7639..64ffe0bf 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = yt_idefix
-version = 0.13.3
+version = 0.13.4
 description = An extension module for yt, adding a frontend for Idefix
 long_description = file: README.md
 long_description_content_type = text/markdown
diff --git a/yt_idefix/__init__.py b/yt_idefix/__init__.py
index b9ee9e25..7856e800 100644
--- a/yt_idefix/__init__.py
+++ b/yt_idefix/__init__.py
@@ -2,4 +2,4 @@
 # immediately after `import yt.extensions.idefix`
 from yt_idefix.api import *
 
-__version__ = "0.13.3"
+__version__ = "0.13.4"
diff --git a/yt_idefix/data_structures.py b/yt_idefix/data_structures.py
index 8795c870..0905e308 100644
--- a/yt_idefix/data_structures.py
+++ b/yt_idefix/data_structures.py
@@ -8,7 +8,7 @@
 from abc import ABC, abstractmethod
 from functools import cached_property
 from importlib.metadata import version
-from typing import Literal, Sequence
+from typing import Literal
 
 import inifix
 import numpy as np
@@ -147,7 +147,14 @@ def _cell_centers(self):
         # with unit "code_length" and dtype float64
         ...
 
-    def _icoords_to_fcoords(self, icoords, ires, axes: Sequence[int] = (0, 1, 2)):
+    def _icoords_to_fcoords(
+        self,
+        icoords: np.ndarray,
+        ires: np.ndarray,
+        axes: tuple[int, ...] | None = None,
+    ):
+        if axes is None:
+            axes = (0, 1, 2)
         # this is needed to support projections
         coords = np.empty(icoords.shape, dtype="f8")
         cell_widths = np.empty(icoords.shape, dtype="f8")