How to use the lpips.util.util.cos_sim function in lpips

def forward(self, in0, in1, retPerLayer=False):
        in0_sc = (in0 - self.shift.expand_as(in0))/self.scale.expand_as(in0)
        in1_sc = (in1 - self.shift.expand_as(in0))/self.scale.expand_as(in0)

        outs0 = self.net.forward(in0_sc)
        outs1 = self.net.forward(in1_sc)

        if(retPerLayer):
            all_scores = []
        for (kk,out0) in enumerate(outs0):
            cur_score = (1.-util.cos_sim(outs0[kk],outs1[kk]))
            if(kk==0):
                val = 1.*cur_score
            else:
                # val = val + self.lambda_feat_layers[kk]*cur_score
                val = val + cur_score
            if(retPerLayer):
                all_scores+=[cur_score]

        if(retPerLayer):
            return (val, all_scores)
        else:
            return val