def __realized_bbox(self, requested_bbox):
    """
    The requested bbox might not be aligned to the underlying chunk grid 
    or even outside the bounds of the dataset. Convert the request into
    a bbox representing something that can be actually downloaded.

    Returns: Bbox
    """
    realized_bbox = requested_bbox.expand_to_chunk_size(self.underlying, offset=self.voxel_offset)
    return Bbox.clamp(realized_bbox, self.bounds)
The requested bbox might not be aligned to the underlying chunk grid 
    or even outside the bounds of the dataset. Convert the request into
    a bbox representing something that can be actually downloaded.

    Returns: Bbox