dynamic insertion into partition based on value in insert for Postgres

gistfile1.sql

create or replace function insert_herp_to_derp()
returns trigger as $$
begin
execute 'INSERT INTO ' || quote_ident('derp_' || NEW.derp_id || '_herps') || ' SELECT ($1).*' using NEW;
return null;
end;                                  
$$ LANGUAGE plpgsql;

CREATE TRIGGER insert_herps_trigger BEFORE INSERT ON herps FOR EACH ROW EXECUTE PROCEDURE insert_herp_to_derp();