original_string: public function execute() {
          global $CFG, $DB;
  
          if (!empty($CFG->gradehistorylifetime)) {
              $now = time();
              $histlifetime = $now - ($CFG->gradehistorylifetime * DAYSECS);
              $tables = [
                  'grade_outcomes_history',
                  'grade_categories_history',
                  'grade_items_history',
                  'grade_grades_history',
                  'scale_history'
              ];
              foreach ($tables as $table) {
                  if ($DB->delete_records_select($table, "timemodified < ?", [$histlifetime])) {
                      mtrace("    Deleted old grade history records from '$table'");
                  }
              }
          }
      }
code: public function execute() {
          global $CFG, $DB;
  
          if (!empty($CFG->gradehistorylifetime)) {
              $now = time();
              $histlifetime = $now - ($CFG->gradehistorylifetime * DAYSECS);
              $tables = [
                  'grade_outcomes_history',
                  'grade_categories_history',
                  'grade_items_history',
                  'grade_grades_history',
                  'scale_history'
              ];
              foreach ($tables as $table) {
                  if ($DB->delete_records_select($table, "timemodified < ?", [$histlifetime])) {
                      mtrace("    Deleted old grade history records from '$table'");
                  }
              }
          }
      }
code_tokens: public function execute ( ) { global $ CFG , $ DB ; if ( ! empty ( $ CFG -> gradehistorylifetime ) ) { $ now = time ( ) ; $ histlifetime = $ now - ( $ CFG -> gradehistorylifetime * DAYSECS ) ; $ tables = [ 'grade_outcomes_history' , 'grade_categories_history' , 'grade_items_history' , 'grade_grades_history' , 'scale_history' ] ; foreach ( $ tables as $ table ) { if ( $ DB -> delete_records_select ( $ table , "timemodified < ?" , [ $ histlifetime ] ) ) { mtrace ( "    Deleted old grade history records from '$table'" ) ; } } } }
docstring: Cleanup history tables.
docstring_tokens: Cleanup history tables .