...
    api.Command[cmd](*args, **options)
  File "/root/freeipa/ipalib/frontend.py", line 443, in __call__
    messages.VersionMissing(server_version=API_VERSION))
  File "/root/freeipa/ipalib/messages.py", line 48, in add_message
    result.setdefault('messages', []).append(message.to_dict())
AttributeError: 'tuple' object has no attribute 'append'

frontend.__call__()

...
        ret = self.run(*args, **options)
        # self.run returns messages in tuple
        if not version_provided and isinstance(ret, dict):
            messages.add_message(
                API_VERSION, ret,
                messages.VersionMissing(server_version=API_VERSION))
...