How to iterate over finite fields

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In my current code I have to iterate over $GF(2^7)$ four times:

en1 = enumerate(gf)
en2 = enumerate(gf)
en3 = enumerate(gf)
en4 = enumerate(gf)

for i,x0 in en1:
    for j,x1 in en2:
        for k,x2 in en3:
            for m,x3 in en4:

In the loop I evaluate some multivariate polynomial. But this is very memory hungry. Is there any better way to do this?