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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 change_disk_usage(self, usage_change, file_path, st_dev):
 """Change the used disk space by the given amount. Args: usage_change: Number of bytes added to the used space. If negative, the used space will be decreased. file_path: The path of the object needing the disk space. st_dev: The device ID for the respective file system. Raises: IOError: if usage_change exceeds the free file system space """

        mount_point = self._mount_point_for_device(st_dev)
        if mount_point:
            total_size = mount_point['total_size']
            if total_size is not None:
                if total_size - mount_point['used_size'] < usage_change:
                    self.raise_io_error(errno.ENOSPC, file_path)
            mount_point['used_size'] += usage_change