python mesos core bindings rejects framework messages with null bytes

We're getting exceptions when sending frameworkMessages, specifically

smf1-aaj-35-sr1.prod.twitter.com: Exception in thread Thread-2:
smf1-aaj-35-sr1.prod.twitter.com: Traceback (most recent call last):
smf1-aaj-35-sr1.prod.twitter.com: File "/usr/lib64/python2.6/threading.py", line 532, in __bootstrap_inner
smf1-aaj-35-sr1.prod.twitter.com: self.run()
smf1-aaj-35-sr1.prod.twitter.com: File "twitter/common/concurrent/deferred.py", line 43, in run
smf1-aaj-35-sr1.prod.twitter.com: self._closure()
smf1-aaj-35-sr1.prod.twitter.com: File "/var/lib/mesos/slaves/201211292101-1968906762-5050-60720-1356/frameworks/201104070004-0000002563-0000/executors/gc-66e0daf8-b527-4d7c-ab17-ff6671acc0ff/runs/0/gc_executor.pex/gc_executor.py", line 207, in <lambda>
smf1-aaj-35-sr1.prod.twitter.com: File "/var/lib/mesos/slaves/201211292101-1968906762-5050-60720-1356/frameworks/201104070004-0000002563-0000/executors/gc-66e0daf8-b527-4d7c-ab17-ff6671acc0ff/runs/0/gc_executor.pex/gc_executor.py", line 195, in run_gc
smf1-aaj-35-sr1.prod.twitter.com: TypeError: argument 1 must be string without null bytes, not str
smf1-aaj-35-sr1.prod.twitter.com:

The Java executor handles strings with \0 bytes just fine.