diff --git a/src/dask_histogram/boost.py b/src/dask_histogram/boost.py
index 3f79269..d445b68 100644
--- a/src/dask_histogram/boost.py
+++ b/src/dask_histogram/boost.py
@@ -166,7 +166,7 @@ def _rebuild(
 
     @property
     def _in_memory_type(self) -> type[bh.Histogram]:
-        if type(self) != Histogram:
+        if type(self) is not Histogram:
             warnings.warn(
                 """dask_histogram.boost.Histogram has been subclassed without
                 overriding '_in_memory_type', please do so if you would like to
diff --git a/tests/test_boost.py b/tests/test_boost.py
index 0dd68f5..c982642 100644
--- a/tests/test_boost.py
+++ b/tests/test_boost.py
@@ -520,7 +520,7 @@ def test_add(use_weights):
 def test_name_assignment():
     import dask.array as da
 
-    hist = pytest.importorskip("hist")
+    pytest.importorskip("hist")
     import hist.dask
 
     x = da.random.normal(size=100)
@@ -545,7 +545,7 @@ def test_histref_pickle():
 
     import dask.array as da
 
-    hist = pytest.importorskip("hist")
+    pytest.importorskip("hist")
     import hist.dask
 
     x = da.random.normal(size=100)