Check if a user-defined type already exists in PostgreSQL

I add here the complete solution for creating types in a simple script, without the need of creating a function just for this purpose.

--create types
DO $$
BEGIN
    IF NOT EXISTS (SELECT 1 FROM pg_type WHERE typname="my_type") THEN
        CREATE TYPE my_type AS
        (
            --my fields here...
        );
    END IF;
    --more types here...
END$$;