擅长:python、mysql、java
<pre><code>if (a is None) != (b is None):
raise SystemExit("kkthxbye")
# remainder of code
</code></pre>
<p><a href="https://stackoverflow.com/questions/4175480/whats-the-difference-between-xor-and-not-equal-to">What's the difference between XOR and NOT-EQUAL-TO?</a></p>