error while parsing config file: decoding to str: need a bytes-like object, Interpolate found

Конфигурация

...
c['change_source'] += [
changes.GitPoller(
util.Interpolate('https://%(secret:user)s:%(secret:password)s@git.specialistoff.net/repo.git'),
workdir='gitpoller-workdir',
branch='master',
pollInterval=300
)
]
...

Ошибка

2021-12-26 22:54:31+0300 [-] error while parsing config file:
        Traceback (most recent call last):
          File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 266, in <lambda>
            inContext.theWork = lambda: context.call(ctx, func, *args, **kw)
          File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 122, in callWithContext
            return self.currentContext().callWithContext(ctx, func, *args, **kw)
          File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 85, in callWithContext
            return func(*args,**kw)
          File "/usr/local/lib/python3.8/dist-packages/buildbot/config.py", line 151, in loadConfig
            filename, config_dict = loadConfigDict(
        --- <exception caught here> ---
          File "/usr/local/lib/python3.8/dist-packages/buildbot/config.py", line 114, in loadConfigDict
            execfile(filename, localDict)
          File "/usr/lib/python3/dist-packages/twisted/python/compat.py", line 247, in execfile
            exec(code, globals, locals)
          File "/home/bmaster/master/master.cfg", line 42, in <module>
            changes.GitPoller(
          File "/usr/local/lib/python3.8/dist-packages/buildbot/changes/gitpoller.py", line 56, in __init__
            super().__init__(repourl, **kwargs)
          File "/usr/local/lib/python3.8/dist-packages/buildbot/util/service.py", line 292, in __init__
            super().__init__(*args, **kwargs)
          File "/usr/local/lib/python3.8/dist-packages/buildbot/util/service.py", line 188, in __init__
            self.name = bytes2unicode(name)
          File "/usr/local/lib/python3.8/dist-packages/buildbot/util/__init__.py", line 272, in bytes2unicode
            return str(x, encoding, errors)
        builtins.TypeError: decoding to str: need a bytes-like object, Interpolate found

2021-12-26 22:54:31+0300 [-] Configuration Errors:
2021-12-26 22:54:31+0300 [-]   error while parsing config file: decoding to str: need a bytes-like object, Interpolate found (traceback in logfile)