diff --git a/src/datasets/features/features.py b/src/datasets/features/features.py
index d58676ce730..4008fec0886 100644
--- a/src/datasets/features/features.py
+++ b/src/datasets/features/features.py
@@ -847,7 +847,7 @@ def to_pylist(self, maps_as_pydicts: Optional[Literal["lossy", "strict"]] = None
 
 
 class PandasArrayExtensionDtype(PandasExtensionDtype):
-    _metadata = "value_type"
+    _metadata = ("value_type",)
 
     def __init__(self, value_type: Union["PandasArrayExtensionDtype", np.dtype]):
         self._value_type = value_type