obfs-flash-client doesn't allow intermixed positional and optional arguments

I was playing with a torrc for obfs-flash and I found that obfs-flash-client doesn't allow options to come between positional arguments:

       works: obfs-flash-client 2334 :9000
       works: obfs-flash-client 2334 :9000 --fp-arg=-4
       works: obfs-flash-client --fp-arg=-4 2334 :9000
doesn't work: obfs-flash-client 2334 --fp-arg=-4 :9000

The "doesn't work" error is

$ ./obfs-flash-client 2334 --fp-arg=-4 :9000
usage: obfs-flash-client [-h] [--fp-arg ARG] PORT [REMOTE:PORT]
obfs-flash-client: error: unrecognized arguments: :9000

I expected intervening options not to affect non-option arguments, like other commands I'm used to. It seems like the behavior is inherent to argparse:

• Issue 14191: argparse doesn't allow optionals within positionals
• Python argparse: Combine optional parameters with nargs=argparse.REMAINDER

If you agree that this is worth changing, a potential workaround is

• http://bugs.python.org/issue14191#msg155185 (and maybe other messages in that bug) optparse works the way I expect, but it is deprecated.