DOC: update the pandas.Index.is_categorical docstring

pandas/core/indexes/base.py

@@ -1156,7 +1156,7 @@ def to_frame(self, index=True):
         >>> idx = pd.Index(['Ant', 'Bear', 'Cow'], name='animal')
         >>> idx.to_frame()
             animal
-        animal       
+        animal
         Ant       Ant
         Bear     Bear
         Cow       Cow
@@ -1471,6 +1471,39 @@ def is_object(self):
         return is_object_dtype(self.dtype)
 
     def is_categorical(self):
+        """
+        Check if the Index holds categorical data.
+
+        Returns
+        -------
+        boolean
+            True if the Index is categorical.
+
+        See Also
+        --------
+        CategoricalIndex : Index for categorical data.
+
+        Examples
+        --------
+        >>> idx = pd.Index(["Watermelon", "Orange", "Apple",
+        ...                 "Watermelon"]).astype("category")
+        >>> idx.is_categorical()
+        True
+
+        >>> idx = pd.Index([1, 3, 5, 7])
+        >>> idx.is_categorical()
+        False
+
+        >>> s = pd.Series(["Peter", "Víctor", "Elisabeth", "Mar"])
+        >>> s
+        0        Peter
+        1       Víctor
+        2    Elisabeth
+        3          Mar
+        dtype: object
+        >>> s.index.is_categorical()
+        False
+        """
         return self.inferred_type in ['categorical']
 
     def is_interval(self):