function_exists

<?php                 if (\function_exists('filter_var')) {

                    $filtered = \filter_var($hexNumberString[1], \FILTER_VALIDATE_INT, \FILTER_FLAG_ALLOW_HEX);

                    if ($filtered !== false) {

                        $content = $filtered;

<?php     protected function validEncoding($value)

    {

        static $encodings;

        if (isset($encodings) === false && \function_exists('mb_list_encodings')) {

            $encodings = \mb_list_encodings();

        }