Backport of a fix for the __loader__.get_data() test.
diff --git a/Lib/test/test_doctest.py b/Lib/test/test_doctest.py
index c3d1bd8..cfee7ec 100644
--- a/Lib/test/test_doctest.py
+++ b/Lib/test/test_doctest.py
@@ -1912,6 +1912,7 @@
        provided.
 
          >>> import unittest, pkgutil, test
+         >>> added_loader = False
          >>> if not hasattr(test, '__loader__'):
          ...     test.__loader__ = pkgutil.get_loader(test)
          ...     added_loader = True