Backtrader - leverage.py error

1.0 leverage.py error

如果成交後，本金不變，會触發0/self._value error。

2.0 debug

def next(self):
    # Updates the leverage for "dtkey" (see base class) for each cycle
    # 0.0 if 100% in cash, 1.0 if no short selling and fully invested
    try:
        lev = (self._value - self._cash) / self._value
    except:
        lev = 0
    self.rets[self.data0.datetime.datetime()] = lev

　　leverage.py，line 61~74。