@rpn_train.setter
def rpn_train(self, val):
    self.RPN.train = val
    if val:
        self._rcnn_train = (not val)
    if (self.rcnn_train or self.rpn_train):
        self.trunk.train = True
    else:
        self.trunk.train = False
@rpn_train.setter
def rpn_train(self, val):
    self.RPN.train = val
    if val:
        self._rcnn_train = (not val)
    if (self.rcnn_train or self.rpn_train):
        self.trunk.train = True
    else:
        self.trunk.train = False