Randomization of selected rows resulted in an error when importing condition: TypeError: Cannot read property 'length' of undefined

Online experiments
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4

i followed Pavlovia: Randomization of selected rows results in error - #2 by Marina_Chrisi
they replaced “$random(40)*159”
the code component they replaced the
if LoopName.thisN==49:
trials.finished=True

so i copied it
if GroupB.thisN==1:
trials.finished=True

but it the ignores it