os.mkdir(path_to_new_dir)
os.makedirs(path_to_new_dir)

os.remove()      remove a file
os.unlink()      (the same)
 
os.rmdir()        single empty directory
os.removedirs()   empty subdirectories as well
shutil.rmtree()   rm -rf 

os.getpid()
os.getppid()