def shouldDestroyCircuit(self, circuit):
        '''Return **True** iff CircuitManager thinks the calling circuit
        should be destroyed.

        Circuits call shouldDestroyCircuit() when their number of open
        streams drops to zero. Since CircuitManager knows about all open
        and pending circuits, it can make an informed judgement about whether
        the calling circuit should be destroyed or remain open.

        Currently, CircuitManager maintains at least 4 open or pending IPv4
        circuits and one open or pending IPv6 circuit. If the number of
        streams on any circuit drops to zero and it can be closed while still
        satisfying these basic constraints, then CircuitManager tells it
        to begin destroying itself (returns True).

        :param oppy.circuit.circuit.Circuit circuit: circuit to
            consider destroying.
        :returns: **bool** **True** if CircuitManager decides this circuit
            should be destroyed, **False** otherwise.
        '''
        # TODO: update for more kinds of circuits
        if circuit.circuit_type == CircuitType.IPv4:
            return self._totalIPv4Count()-1 > self._min_IPv4_count
        else:
            return self._totalIPv6Count()-1 > self._min_IPv6_count

    # TODO: fix docs to reflect CircuitBuildTask changes
dataset/ETHPy150Open nskinkel/oppy/oppy/circuit/circuitmanager.py/CircuitManager.shouldDestroyCircuit/original