Nicer errors when I forget to install bzr?

[Deleted user]

voltagex@dream:~/src$ git bzr clone lp:windows-ssh-server windows-ssh-server
Traceback (most recent call last):
  File "/home/voltagex/bin/git-bzr", line 709, in <module>
    sys.exit(main(sys.argv))
  File "/home/voltagex/bin/git-bzr", line 703, in main
    return func(argv[2:])
  File "/home/voltagex/bin/git-bzr", line 411, in cmd_clone
    init_repo(cl)
  File "/home/voltagex/bin/git-bzr", line 348, in init_repo
    bzr(['init-repo', '--no-trees', cl.bzr_dir()])
  File "/home/voltagex/bin/git-bzr", line 63, in bzr
    return run_command(cmd, **kwargs)
  File "/home/voltagex/bin/git-bzr", line 37, in run_command
    proc = subprocess.Popen(cmd, stdout=stdout, stdin=stdin)
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory