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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 read(self, memory, addr, length):
 """ Read the specified amount of bytes from the given memory at the given address """

        if memory.id in self._read_requests:
            logger.warning('There is already a read operation ongoing for '
                           'memory id {}'.format(memory.id))
            return False

        rreq = _ReadRequest(memory, addr, length, self.cf)
        self._read_requests[memory.id] = rreq

        rreq.start()

        return True