BUG: adds stacklevel to warning call

Author: deniederhut

pandas/core/generic.py

@@ -3361,7 +3361,8 @@ def __setattr__(self, name, value):
                     warnings.warn("Pandas doesn't allow Series to be assigned "
                                   "into nonexistent columns - see "
                                   "https://pandas.pydata.org/pandas-docs/"
-                                  "stable/indexing.html#attribute-access")
+                                  "stable/indexing.html#attribute-access",
+                                  stacklevel=2)
                 object.__setattr__(self, name, value)
 
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