random UNique Dict

i have code random unique number star from 1 until 15
my code is sukses use dictionary with loop while
but in this moment i want modifikasi with for or for each what must code change
this my code

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it is sucses but i want to change loop use for or for each what must to do this bellow my code not runing perfect

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That method is not the most efficient. I guess it might go something like:

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Thank you Kaper