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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 register_signal(alias: str, signal: pyqtSignal):
 """ Used to register signal at the dispatcher. Note that you can not use alias that already exists. :param alias: Alias of the signal. String. :param signal: Signal itself. Usually pyqtSignal instance. :return: """

        if SignalDispatcher.signal_alias_exists(alias):
            raise SignalDispatcherError('Alias "' + alias + '" for signal already exists!')

        SignalDispatcher.signals[alias] = signal