protected function check_indicators_requirements() {

        foreach ($this->indicators as $indicator) {
            $missingrequired = $this->check_indicator_requirements($indicator);
            if ($missingrequired !== true) {
                throw new \core_analytics\requirements_exception(get_class($indicator) . ' indicator requires ' .
                    json_encode($missingrequired) . ' sample data which is not provided by ' . get_class($this));
            }
        }
    }