I want to start a block located by typing in expInfo 'session'

I want to control one of blocks start first by typing session information at begining.
I tried to insert a code to stop one of blocks to get a similar effect. But it seems wrong.
Any advice would be very grateful! I just start learning psychopy, thank for all help!

Please show us what you did (i.e. show us your code), and what went wrong.

But to start with, you will need to insert another, outer loop, that encompasses both of the inner loops. This outer loop will run twice, so that on each iteration, just the chosen inner loops gets a chance to run.

Thanks for your help. I have solved this problem by separating two block into two difference experiment program. Even then it may looked primitive.