about model.train()

[EEWenbinWu]

Do we have to use this train func when we train a model？

def train(self, mode=True): 
       """Convert the model into training mode."""
        super().train(mode)
        if mode and self.norm_eval: 
                for m in self.modules():
                        if isinstance(m, _BatchNorm):
                            m.eval()