From 9798fddf9edd037808ab8485f9fb182136558a20 Mon Sep 17 00:00:00 2001
From: crusaderky <crusaderky@gmail.com>
Date: Tue, 2 Jan 2024 14:15:31 +0000
Subject: [PATCH] polish

---
 dask/base.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/dask/base.py b/dask/base.py
index f5f31ebfd03..547bb4063a1 100644
--- a/dask/base.py
+++ b/dask/base.py
@@ -225,8 +225,10 @@ def is_dask_collection(x) -> bool:
         # Read: https://github.com/dask/dask/pull/10676
         return True
 
+    # xarray, pint, and possibly other wrappers always define a __dask_graph__ method,
+    # but it may return None if they wrap around a non-dask object.
     # In all known dask collections other than dask-expr,
-    # calling __dask_graph__ is cheap
+    # calling __dask_graph__ is cheap.
     return x.__dask_graph__() is not None