python empty argument
<p>how do I print help info if no arguments are passed to python script?</p>

<pre><code>#!/usr/bin/env python

import sys

for arg in sys.argv:
    if arg == "do":
        do this
    if arg == ""
        print "usage is bla bla bla"
</code></pre>

<p>what I'm missing is <code>if arg == ""</code> line that I don't know how to express :( </p>
