How to build a block contain two kinds SOA conditions and randomize it?

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OS: Sierra 10.12.6
PsychoPy version: v2021.1.4

Hello everyone!
I want to build an anticue task, but I have a problem to build up…
There will be two conditions in one block, one conditon is 40-SOA, the other one is 600-SOA,
I want to write both conditions in one block…

This is 40-SOA condition and 600-SOA condition

And I want to these conditions(T1~T8) show totally random in Block1.
for example,

I don’t know how to do it.
Any advice is welcome! Thanks for your time.