def METHOD_NAME(self, *data):
    loss = self.model(*data)
    loss.mean().backward()
    loss = reduce_value(loss, dst=None)
    self.metrics.train.loss.update(loss)
    self.metrics.train.bc_loss.update(self.model.bc_loss)
    self.metrics.train.fc_loss.update(self.model.fc_loss)