Problems after switching to Base

Learning
5

It doesn’t seem like you want to mix modules here, but if you did you could do either:

let module S = Some_module in

S.print_endline "..." ...; (* Module's print_endline *)
print_endline "..." .. (* Std print_endline *)

or

lets special_print_endline = Some_module.print_endline in

special_print_endline "" ...;
print_endline "" ...