def get_per_pixel_mean(names=('train', 'test', 'extra')):
        """
        Args:
            names (tuple[str]): names of the dataset split

        Returns:
            a 32x32x3 image, the mean of all images in the given datasets
        """
        for name in names:
            assert name in ['train', 'test', 'extra'], name
        images = [SVHNDigit(x).X for x in names]
        return np.concatenate(tuple(images)).mean(axis=0)

        Args:
            names (tuple[str]): names of the dataset split

        Returns:
            a 32x32x3 image, the mean of all images in the given datasets
        
tensorpack/dataflow/dataset/svhn.py