defhash problem => qw/name level statement owner author/;
defhash contest => qw/start end name owner/;
-defhash job => qw/date extension filesize private problem result result_text user/;
+defhash job => qw/date errors extension filesize private problem result result_text user/;
defhash user => qw/name email town university level/;
sub clean_job (_){