def mutator_stage(func):

    def coro(*args):
        task = None
        while True:
            task = yield task
            func(*(args + (task,)))
    return coro
Check correct errors are raised when bad input is given.
dataset/ETHPy150Open beetbox/beets/beets/util/pipeline.py/mutator_stage--crossover with--dataset/ETHPy150Open lisa-lab/pylearn2/pylearn2/linear/tests/test_cudnn.py/TestCudnn.test_value_errors