def removeSystemEventTrigger(triggerID):
    """
        Removes a trigger added with addSystemEventTrigger.

        @param triggerID: a value returned from addSystemEventTrigger.

        @raise KeyError: If there is no system event trigger for the given
            C{triggerID}.

        @raise ValueError: If there is no system event trigger for the given
            C{triggerID}.

        @raise TypeError: If there is no system event trigger for the given
            C{triggerID}.
        """
