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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 project_masks_on_boxes(segmentation_masks, proposals, discretization_size):
 """ Given segmentation masks and the bounding boxes corresponding to the location of the masks in the image, this function crops and resizes the masks in the position defined by the boxes. This prepares the masks for them to be fed to the loss computation as the targets. Arguments: segmentation_masks: an instance of SegmentationMask proposals: an instance of BoxList """

    masks = []
    M = discretization_size
    device = proposals.bbox.device
    proposals = proposals.convert("xyxy")
    assert segmentation_masks.size == proposals.size, "{}, {}".format(
        segmentation_masks, proposals
    )
    # TODO put the proposals on the CPU, as the representation for the
    # masks is not efficient GPU-wise (possibly several small tensors for
    # representing a single instance mask)
    proposals = proposals.bbox.to(torch.device("cpu"))
    for segmentation_mask, proposal in zip(segmentation_masks, proposals):
        # crop the masks, resize them to the desired resolution and
        # then convert them to the tensor representation,
        # instead of the list representation that was used
        cropped_mask = segmentation_mask.crop(proposal)
        scaled_mask = cropped_mask.resize((M, M))
        mask = scaled_mask.convert(mode="mask")
        masks.append(mask)
    if len(masks) == 0:
        return torch.empty(0, dtype=torch.float32, device=device)
    return torch.stack(masks, dim=0).to(device, dtype=torch.float32)