I cannot run random access for LAMP

[kwonjueun]

Dear Mark
I really pleasure on your works.
I runned LAMP.py in Bernoulli trials and it worked very well.
But in random access(line 25 in LAMP.py) , I cannot execute this code.
Error occurs because of absence of 'A_' in random access.
How can I run it?

Have a nice day.