fix C401 warning

Author: shdongre

pandas/tests/base/test_misc.py

@@ -160,7 +160,7 @@ def test_searchsorted(request, index_or_series_obj):
         mark = pytest.mark.xfail(reason="complex objects are not comparable")
         request.applymarker(mark)
 
-    elif len(set(type(x) for x in obj)) > 1 and isinstance(obj, Index):
+    elif len({type(x) for x in obj}) > 1 and isinstance(obj, Index):
         mark = pytest.mark.xfail(reason="np.searchsorted doesn't work on mixed types")
         request.applymarker(mark)