SF patch 1631942 by Collin Winter:
(a) "except E, V" -> "except E as V"
(b) V is now limited to a simple name (local variable)
(c) V is now deleted at the end of the except block
diff --git a/Lib/doctest.py b/Lib/doctest.py
index 435e13b..d120a01 100644
--- a/Lib/doctest.py
+++ b/Lib/doctest.py
@@ -1604,8 +1604,8 @@
          ...                                    {}, 'foo', 'foo.py', 0)
          >>> try:
          ...     runner.run(test)
-         ... except UnexpectedException, failure:
-         ...     pass
+         ... except UnexpectedException as f:
+         ...     failure = f
 
          >>> failure.test is test
          True
@@ -1632,8 +1632,8 @@
 
          >>> try:
          ...    runner.run(test)
-         ... except DocTestFailure, failure:
-         ...    pass
+         ... except DocTestFailure as f:
+         ...    failure = f
 
        DocTestFailure objects provide access to the test:
 
@@ -2141,8 +2141,8 @@
              >>> case = DocTestCase(test)
              >>> try:
              ...     case.debug()
-             ... except UnexpectedException, failure:
-             ...     pass
+             ... except UnexpectedException as f:
+             ...     failure = f
 
            The UnexpectedException contains the test, the example, and
            the original exception:
@@ -2170,8 +2170,8 @@
 
              >>> try:
              ...    case.debug()
-             ... except DocTestFailure, failure:
-             ...    pass
+             ... except DocTestFailure as f:
+             ...    failure = f
 
            DocTestFailure objects provide access to the test: