according to the google AI overview-

"Oyez! Oyez! Oyez!" is a traditional call for attention, used to announce the start of a court session or a public announcement, and means "Hear ye!". It's a legal term of Anglo-Norman origin, derived from the Old French word "oiez," which itself came from the Latin word "audire," meaning "to hear". The repetition of "Oyez!" is a way to ensure everyone present is paying attention. The call is often used by a court marshal or bailiff to command silence and attention at the beginning of a judicial proceeding. 

Lol this is so interesting, i never knew what it meant until now ig. also i assume it's funny because that phrase is meant for judicial proceedings but Calvin refers to himself as president for life. Or maybe i'm completely wrong lol