Attempt the question, check the explanation, and continue with similar questions to build confidence before exams.
np.savetxt('output.txt', data, delimiter=',')
np.save('output.txt', data)
np.savetxt(data, 'output.txt', delimiter=',')
np.savez('output.txt', data)
Continue with nearby questions to strengthen the same chapter concept while you still have the context fresh in mind.