diff --git a/python-package/xgboost/dask.py b/python-package/xgboost/dask.py
index 579e4dd4f2b8..0d3eb7cf159f 100644
--- a/python-package/xgboost/dask.py
+++ b/python-package/xgboost/dask.py
@@ -1551,7 +1551,7 @@ async def _async_wrap_evaluation_matrices(
     """A switch function for async environment."""
 
     def _dispatch(ref: Optional[DaskDMatrix], **kwargs: Any) -> DaskDMatrix:
-        if tree_method == "hist" or tree_method == "gpu_hist":
+        if tree_method in ("hist", "gpu_hist"):
             return DaskQuantileDMatrix(
                 client=client, ref=ref, max_bin=max_bin, **kwargs
             )
diff --git a/python-package/xgboost/sklearn.py b/python-package/xgboost/sklearn.py
index 9b0188e68817..d820ccc01f87 100644
--- a/python-package/xgboost/sklearn.py
+++ b/python-package/xgboost/sklearn.py
@@ -910,7 +910,7 @@ def _duplicated(parameter: str) -> None:
 
     def _create_dmatrix(self, ref: Optional[DMatrix], **kwargs: Any) -> DMatrix:
         # Use `QuantileDMatrix` to save memory.
-        if self.tree_method == "hist" or self.tree_method == "gpu_hist":
+        if self.tree_method in ("hist", "gpu_hist"):
             try:
                 return QuantileDMatrix(
                     **kwargs, ref=ref, nthread=self.n_jobs, max_bin=self.max_bin