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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _is_allowed(attr, *args):
 """ Test if a given attribute is allowed according to the current set of configured service backends. """

    for backend in _get_backends():
        try:
            if getattr(backend, attr)(*args):
                return True
        except AttributeError:
            raise NotImplementedError("%s.%s.%s() not implemented" % (
                backend.__class__.__module__, backend.__class__.__name__, attr)
            )
    return False