def register_read(self, fd, callback):
        """Register `fd` for select.  Will `callback` when readable."""
        assert self._rcallbacks not in fd
        self._rcallbacks[fd] = callback
        self.control(SelectTask.NEWFD)
        #self.logger.debug('Registered %s for read on %d', callback, fd)
dataset/ETHPy150Open facebook/sparts/sparts/tasks/select.py/SelectTask.register_read/swapped operands of `not in`