Python: Opening a folder in Explorer/Nautilus/Finder

I am surprised no one has mentioned using xdg-open for *nix which will work for both files and folders:

import os
import platform
import subprocess

def open_file(path):
    if platform.system() == "Windows":
        os.startfile(path)
    elif platform.system() == "Darwin":
        subprocess.Popen(["open", path])
    else:
        subprocess.Popen(["xdg-open", path])