Regarding the phenomenon that cheating is repeatedly banned, a certain class of a certain college promised that as long as the whole class signed the letter of commitment, then if one person in the class cheated, the test results of the whole class would fail. This promise of the class. As a result, some people still cheated in the class, but the class leader's test score was excellent. The conclusion from the above judgment logic is:. ['The class leader took improper measures to prevent the school from strictly implementing its commitments.', 'Most people in the class did not cheat.', 'No one in the class signed the letter of commitment.', 'Someone in the class did not sign the letter of commitment.']