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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 get_cuda_visible_devices():
 """Get the device IDs in the CUDA_VISIBLE_DEVICES environment variable. Returns: if CUDA_VISIBLE_DEVICES is set, this returns a list of integers with the IDs of the GPUs. If it is not set, this returns None. """

    gpu_ids_str = os.environ.get("CUDA_VISIBLE_DEVICES", None)

    if gpu_ids_str is None:
        return None

    if gpu_ids_str == "":
        return []

    return [int(i) for i in gpu_ids_str.split(",")]