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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 remove(self, bw):
 """ Removes a buffer watch identifier. @type bw: L{BufferWatch} @param bw: Buffer watch identifier. @raise KeyError: The buffer watch identifier was already removed. """

        try:
            self.__ranges.remove(bw)
        except KeyError:
            if not bw.oneshot:
                raise