question: add the passed user to the free user group list . concode_field_sep List<User> paidGroup concode_elem_sep List<User> freeGroup concode_field_sep void addUserToPaidGroup concode_elem_sep boolean isPaid
target: void function ( final User arg0 ) { if ( paidGroup . contains ( arg0 ) ) { throw new IllegalArgumentException ( "srini_string" ) ; } else { if ( ! freeGroup . contains ( arg0 ) ) { freeGroup . add ( arg0 ) ; } } }