def _momentum_update_key_encoder(self, m=0.999):
        """
        Momentum update of the key encoder
        """
        for param_q, param_k in zip(self.parameters(), self.model_ts[0].parameters()):
            param_k.data = param_k.data * m + param_q.data * (1. - m)

        Momentum update of the key encoder
        
fastreid/modeling/meta_arch/distiller.py