bpo-36326: Let inspect.getdoc() find docstrings for __slots__ (GH-12498)


diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index b9072e0..bc675aa 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -375,6 +375,11 @@
         self.assertEqual(inspect.getsource(obj),
                          self.sourcerange(top, bottom))
 
+class SlotUser:
+    'Docstrings for __slots__'
+    __slots__ = {'power': 'measured in kilowatts',
+                 'distance': 'measured in kilometers'}
+
 class TestRetrievingSourceCode(GetSourceBase):
     fodderModule = mod
 
@@ -429,6 +434,10 @@
                          'A longer,\n\nindented\n\ndocstring.')
         self.assertEqual(inspect.getdoc(git.abuse),
                          'Another\n\ndocstring\n\ncontaining\n\ntabs')
+        self.assertEqual(inspect.getdoc(SlotUser.power),
+                         'measured in kilowatts')
+        self.assertEqual(inspect.getdoc(SlotUser.distance),
+                         'measured in kilometers')
 
     @unittest.skipIf(sys.flags.optimize >= 2,
                      "Docstrings are omitted with -O2 and above")
diff --git a/Lib/test/test_statistics.py b/Lib/test/test_statistics.py
index 485ffe2..7f7839d 100644
--- a/Lib/test/test_statistics.py
+++ b/Lib/test/test_statistics.py
@@ -2051,7 +2051,7 @@
         nd = statistics.NormalDist(300, 23)
         with self.assertRaises(TypeError):
             vars(nd)
-        self.assertEqual(nd.__slots__, ('mu', 'sigma'))
+        self.assertEqual(tuple(nd.__slots__), ('mu', 'sigma'))
 
     def test_instantiation_and_attributes(self):
         nd = statistics.NormalDist(500, 17)