<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def release(self, device_info):
 """This function is called by the segmentation state machine when it has finished with the device information."""

        if _debug: DeviceInfoCache._debug("release %r", device_info)

        # this information record might be used by more than one SSM
        if device_info._ref_count == 0:
            raise RuntimeError("reference count")

        # decrement the reference count
        device_info._ref_count -= 1