decis execut committe decemb improv practic judici cooper combat drug traffick sch execut committe regard articl convent implement schengen agreement hereinaft quot schengen convent quot regard articl abovement convent decid improv practic judici cooper combat drug traffick contract parti undertak request parti intend enforc request mutual assist intend enforc part inform request parti reason refus condit met request enforc decis enter forc state parti schengen convent notifi procedur requir legal system decis bind territori complet pari decemb chairman lamassour