Relying on People v. Panizzon (1996) 13 Cal. 4th 68, 913 P.2d 1061, the People argue that the appeal must be dismissed because review of alleged sentencing error after a plea requires a certificate of probable cause to appeal. In Pannizon, our Supreme Court held "a constitutional challenge to a negotiated sentence imposed as part of a plea bargain is properly viewed as a challenge to the validity of the plea itself" and requires a certificate of probable cause to appeal. (Id., at p. 79; accord, People v. Young (2000) 77 Cal. App. 4th 827, 832 a challenge to the constitutionality of the maximum sentence also requires a certificate.)