Add issue reference

miker985 · miker985 · commit 3d955d1837f8 · 2018-07-30T07:57:05.000-07:00
diff --git a/pandas/core/arrays/categorical.py b/pandas/core/arrays/categorical.py
@@ -631,7 +631,7 @@ def from_codes(cls, codes, categories, ordered=False):
             categorical. If not given, the resulting categorical will be
             unordered.
         """
-        codes = np.asarray(codes)
+        codes = np.asarray(codes)  # #21767
         if not is_integer_dtype(codes):
             msg = "codes need to be array-like integers"
             if is_float_dtype(codes):
