code: def fuse_batchnorm_weights(gamma, beta, mean, var, epsilon):
      # https://github.com/Tencent/ncnn/blob/master/src/layer/batchnorm.cpp
      
      scale = gamma / np.sqrt(var + epsilon)
      bias = beta - gamma * mean / np.sqrt(var + epsilon)
      return [scale, bias]
docs: float sqrt_var = sqrt(var_data[i]);
          a_data[i] = bias_data[i] - slope_data[i] * mean_data[i] / sqrt_var;
          b_data[i] = slope_data[i] / sqrt_var;
          ...
          ptr[i] = b * ptr[i] + a;