Fix categorical_order

seaborn/utils.py

@@ -419,16 +419,32 @@ def axes_ticklabels_overlap(ax):
 def categorical_order(values, order=None):
     """Return a list of unique data values.
 
+    Determine an ordered list of levels in ``values``.
+
+    Parameters
+    ----------
+    values : list, array, Categorical, or Series
+        Vector of "categorical" values
+    order : list-like, optional
+        Desired order of category levels to override the order determined
+        from the ``values`` object.
+
+    Returns
+    -------
+    order : list
+        Ordered list of category levels
+
     """
     if order is None:
-        if hasattr(values, "cat"):
-            order = values.cat.categories
-        elif hasattr(values, "categories"):
+        if hasattr(values, "categories"):
             order = values.categories
         else:
             try:
-                order = values.unique()
-            except AttributeError:
-                order = pd.unique(values)
+                order = values.cat.categories
+            except (TypeError, AttributeError):
+                try:
+                    order = values.unique()
+                except AttributeError:
+                    order = pd.unique(values)
 
     return list(order)