This seems related, might even be the same, but fails with a different case/error message:
#-- begin code-- import argparse import sys parser = argparse.ArgumentParser() parser.add_argument("--log-file", "-l", default=sys.stderr, type=argparse.FileType('a')) args = parser.parse_args() #-- end code-- $ python bin/test-broken.py usage: test-broken.py [-h] [--log-file LOG_FILE] test-broken.py: error: argument --log-file/-l: invalid FileType('a') value: <open file '<stderr>', mode 'w' at 0x7f201a0fc270> -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1048710 Title: Regression in argparse for Python 2.7, 3.2 and 3.3 To manage notifications about this bug go to: https://bugs.launchpad.net/python/+bug/1048710/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs