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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 image_get_root_disk_size(self, image_name):
 """Get the root disk size of the image :param image_name: the image name in image Repository :returns: the disk size in units CYL or BLK """

        try:
            return self._imageops.image_get_root_disk_size(image_name)
        except exception.SDKBaseException:
            LOG.error("Failed to get root disk size units of image '%s'" %
                      image_name)
            raise