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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 coordinator(self):
 """Get the current coordinator Returns: the current coordinator id or None if it is unknown """

        if self.coordinator_id is None:
            return None
        elif self._client.is_disconnected(self.coordinator_id):
            self.coordinator_dead('Node Disconnected')
            return None
        else:
            return self.coordinator_id