def __init__(self, *args, **kwargs):
        if kwargs in 'writer':
            super(PassthroughWrite, self).__setattr__('_reader', kwargs['writer'])
        else:
            raise ContainerError("A writer is required.")
        super(PassthroughWrite, self).__init__(*args, **kwargs)
dataset/ETHPy150Open biocore/pyqi/pyqi/core/container.py/PassthroughWrite.__init__/swapped operands of `in`