misleading error for bzr branches you don't have access to

have a config that when run spits out an error:

Traceback (most recent call last):
  File "/srv/prodstack/isd/config-manager/cm.py", line 30, in <module>
    main(sys.argv)
  File "/srv/prodstack/isd/config-manager/lib/config_manager/__init__.py", line 375, in main
    config.build(os.path.abspath(os.curdir))
  File "/srv/prodstack/isd/config-manager/lib/config_manager/__init__.py", line 74, in build
    entry.build(dir)
  File "/srv/prodstack/isd/config-manager/lib/config_manager/__init__.py", line 280, in build
    raise ValueError("unknown url type '%s'" % self.url)
ValueError: unknown url type 'bzr+ssh://bazaar.launchpad.net/~canonical-sizzle/canonical-sizzle/trunk;revno=79'

What it's really saying is "you don't have permission to access this branch"