legal ground
Article 174th of the Criminal Procedure Law of People's Republic of China (PRC)
If a criminal suspect voluntarily pleads guilty and agrees to apply sentencing suggestions and procedures, he shall sign a confession and repentance in the presence of a defender or a lawyer on duty. If a criminal suspect pleads guilty and admits punishment, it is not necessary to sign a confession and repentance book under any of the following circumstances:
(1) The criminal suspect is a mental patient who is blind, deaf, dumb or has not completely lost the ability to recognize or control his own behavior;
(two) the legal representative or defender of the juvenile criminal suspect has any objection to the juvenile's confession and punishment;
(3) Other circumstances in which it is not necessary to sign a confession and repentance.