CLN: raise correct error for Panel sort_values

pandas/core/generic.py

@@ -2366,9 +2366,14 @@ def add_suffix(self, suffix):
         1   A    1    1
         """
 
-    def sort_values(self, by, axis=0, ascending=True, inplace=False,
+    def sort_values(self, by=None, axis=0, ascending=True, inplace=False,
                     kind='quicksort', na_position='last'):
-        raise AbstractMethodError(self)
+        """
+        NOT IMPLEMENTED: do not call this method, as sorting values is not
+        supported for Panel objects and will raise an error.
+        """
+        raise NotImplementedError("sort_values has not been implemented "
+                                  "on Panel or Panel4D objects.")
 
     _shared_docs['sort_index'] = """
         Sort object by labels (along an axis)

pandas/tests/test_panel.py

@@ -2429,6 +2429,11 @@ def test_all_any_unhandled(self):
         pytest.raises(NotImplementedError, self.panel.all, bool_only=True)
         pytest.raises(NotImplementedError, self.panel.any, bool_only=True)
 
+    # GH issue 15960
+    def test_sort_values(self):
+        pytest.raises(NotImplementedError, self.panel.sort_values)
+        pytest.raises(NotImplementedError, self.panel.sort_values, 'ItemA')
+
 
 class TestLongPanel(object):
     """

pandas/tests/test_panel4d.py

@@ -939,3 +939,8 @@ def test_rename(self):
 
     def test_get_attr(self):
         tm.assert_panel_equal(self.panel4d['l1'], self.panel4d.l1)
+
+    # GH issue 15960
+    def test_sort_values(self):
+        pytest.raises(NotImplementedError, self.panel4d.sort_values)
+        pytest.raises(NotImplementedError, self.panel4d.sort_values, 'ItemA')