* Tighten up psf/black and flake8
* Fix some tests
* Fix some E741
* Fix some E741
* updating DIRECTORY.md
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
* add gaussian filter algorithm and lena.jpg
* add img_convolve algorithm and sobel_filter
* add canny edge detection algorithm and modify sobel_filter
* format to avoid the backslashes