Attempt the question, check the explanation, and continue with similar questions to build confidence before exams.
np.savetxt('file.txt', arr, fmt='%i')
np.savetxt('file.txt', arr, fmt='int')
np.savetxt(arr, 'file.txt', fmt='%i')
np.savetxt(arr, 'file.txt', fmt=int)
Continue with nearby questions to strengthen the same chapter concept while you still have the context fresh in mind.