concrete/src/File/Image/Svg/SanitizerOptions.php
protected function normalizeStringList($value)
    {
        if (is_string($value)) {
            $strings = preg_split('/\s+/', $value, -1, PREG_SPLIT_NO_EMPTY);
        } elseif (is_array($value)) {
            $strings = array_map('trim', array_map('strval', $value));
        } else {
            $strings = [];
        }

        return array_values(array_unique(array_map('strtolower', $strings)));
    }
protected function normalizeStringList($value)
    {
        if (is_string($value)) {
            $strings = preg_split('/\s+/', $value, -1, PREG_SPLIT_NO_EMPTY);
        } elseif (is_array($value)) {
            $strings = array_map('trim', array_map('strval', $value));
        } else {
            $strings = [];
        }

        return array_values(array_unique(array_map('strtolower', $strings)));
    }
protected function normalizeStringList ( $ value ) { if ( is_string ( $ value ) ) { $ strings = preg_split ( '/\s+/' , $ value , - 1 , PREG_SPLIT_NO_EMPTY ) ; } elseif ( is_array ( $ value ) ) { $ strings = array_map ( 'trim' , array_map ( 'strval' , $ value ) ) ; } else { $ strings = [ ] ; } return array_values ( array_unique ( array_map ( 'strtolower' , $ strings ) ) ) ; }
Takes an array, keeps only strings, makes them lowercase, and returns the unique values.

@param string|array $value

@return string[]
Takes an array keeps only strings makes them lowercase and returns the unique values .