def create_set(values):
    return set(dict.fromkeys(values))
 
# em vez de sample, vou criar uma lista com todos os números pares de 2 a 500
# só para o teste não depender de aleatoriedade
l1 = list(range(2, 501, 2))
 
from timeit import timeit
 
# executa mil vezes cada teste
params = { 'number' : 1000, 'globals': globals() }
 
# imprime os tempos em segundos (for demora mais que set)
print(timeit('l2 = list(range(1000))\nl2 = list(create_set(l2) - create_set(l1))', **params))
print(timeit('l2 = list(range(1000))\nfor i in l1:\n  l2.remove(i)', **params))

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