-from os import path as os_path, mkdir, rmdir, system, walk, stat as os_stat, listdir, readlink, makedirs, error as os_error, symlink
+from os import path as os_path, mkdir, rmdir, system, walk, stat as os_stat, listdir, readlink, makedirs, error as os_error, symlink, access, F_OK, R_OK, W_OK