protected static function normalizeHelper($number, array $normalizationReplacements, $removeNonMatches)
    {
        $normalizedNumber = '';
        $strLength = mb_strlen($number, 'UTF-8');
        for ($i = 0; $i < $strLength; $i++) {
            $character = mb_substr($number, $i, 1, 'UTF-8');
            if (isset($normalizationReplacements[mb_strtoupper($character, 'UTF-8')])) {
                $normalizedNumber .= $normalizationReplacements[mb_strtoupper($character, 'UTF-8')];
            } elseif (!$removeNonMatches) {
                $normalizedNumber .= $character;
            }
            // If neither of the above are true, we remove this character.
        }
        return $normalizedNumber;
    }