What is the test for obtaining a certificate of probable cause to appeal a guilty or nolo contendere plea?

constitutional, jurisdictional, or other grounds going to the legality of the proceedings. [] (b) The trial court has executed and filed a certificate of probable cause for such appeal with the county clerk.' [ ] Notwithstanding the broad language of section 1237.5, it is settled that two types of issues may be raised in a guilty or nolo contendere plea appeal without issuance of a certificate: (1) search and seizure issues for which an appeal is provided under section 1538.5, subdivision (m); and (2) issues regarding proceedings held subsequent to the plea for the purpose of determining the degree of the crime and the penalty to be imposed." (People v. Panizzon (1996) 13 Cal.4th 68, 74-75.)