Python: Random sequence
<p>I have the following code:</p>

<pre><code>import string
import random

d =[random.choice(string.uppercase) for x in xrange(3355)]
s = "".join(d)

print s
</code></pre>

<p>At the moment it prints out a random sequence of letters from the alphabet. But, i need it to print out a sequence of letters containing only four letters for example 'A', 'C', 'U', 'G'. How would this be accomplished? </p>

<p>Thanks</p>

<p>Quinn</p>
