What is the default way to validate query string parameters in a rest endpoint? [closed]

I am designing a REST API using Python and Flask.

I'm curious, what should happen in case someone inputs an invalid query string parameter?

GET https://www.example.com/users?page=1;count=20;dummyinvalidparameter=dummyvalue

what if user for instance inputs a a query parameter called dummyinvalidparameter? Should my code throw a 400 Bad Request in this case?