The patch causes three errors:

======================================================================
ERROR: test_anydbm_access (test.test_dbm.TestCase-dbm.dumb)
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Traceback (most recent call last):
  File "/home/heimes/dev/python/py3k/Lib/test/test_dbm.py", line 92, in
test_anydbm_access
    f = dbm.open(_fname, 'r')
  File "/home/heimes/dev/python/py3k/Lib/dbm/__init__.py", line 79, in open
    raise error[0]("need 'c' or 'n' flag to open new db")
dbm.error: need 'c' or 'n' flag to open new db

======================================================================
ERROR: test_anydbm_keys (test.test_dbm.TestCase-dbm.dumb)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/heimes/dev/python/py3k/Lib/test/test_dbm.py", line 86, in
test_anydbm_keys
    f = dbm.open(_fname, 'r')
  File "/home/heimes/dev/python/py3k/Lib/dbm/__init__.py", line 79, in open
    raise error[0]("need 'c' or 'n' flag to open new db")
dbm.error: need 'c' or 'n' flag to open new db

======================================================================
ERROR: test_anydbm_read (test.test_dbm.TestCase-dbm.dumb)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/heimes/dev/python/py3k/Lib/test/test_dbm.py", line 80, in
test_anydbm_read
    f = dbm.open(_fname, 'r')
  File "/home/heimes/dev/python/py3k/Lib/dbm/__init__.py", line 79, in open
    raise error[0]("need 'c' or 'n' flag to open new db")
dbm.error: need 'c' or 'n' flag to open new db

----------------------------------------------------------------------
Ran 16 tests in 0.429s

FAILED (errors=3)