controller.py

                )
            if voucher.number in self._unpaid:
                return attr.evolve(
                    voucher,
                    state=model_Unpaid(finished=self._unpaid[voucher.number]),
                )
            if voucher.number in self._error:
                return attr.evolve(
                    voucher,
                    state=self._error[voucher.number],
                )
        return voucher


def get_redeemer(plugin_name, node_config, announcement, reactor):
    section_name = "storageclient.plugins.{}".format(plugin_name)
    redeemer_kind = node_config.get_config(
        section=section_name,
        option="redeemer",
        default="ristretto",
    )
    return _REDEEMERS[redeemer_kind](section_name, node_config, announcement, reactor)


_REDEEMERS = {
    "non": NonRedeemer.make,
    "dummy": DummyRedeemer.make,
    "double-spend": DoubleSpendRedeemer.make,
    "unpaid": UnpaidRedeemer.make,
    "error": ErrorRedeemer.make,
    "ristretto": RistrettoRedeemer.make,
}


@inlineCallbacks
def bracket(first, last, between):
    """
    Invoke an action between two other actions.

    :param first: A no-argument function that may return a Deferred.  It is
        called first.

    :param last: A no-argument function that may return a Deferred.  It is
        called last.

    :param between: A no-argument function that may return a Deferred.  It is
        called after ``first`` is done and completes before ``last`` is called.

    :return Deferred: A ``Deferred`` which fires with the result of
        ``between``.
    """
    yield first()
    try:
        result = yield between()
    except GeneratorExit:
        raise
    except:
        info = exc_info()
        yield last()
        if PY2:
            exec("raise info[0], info[1], info[2]")
        raise
    else:
        yield last()
        returnValue(result)