private static function cleanComplex($complexNumber)
    {
        if ($complexNumber[0] == '+') {
            $complexNumber = substr($complexNumber, 1);
        }
        if ($complexNumber[0] == '0') {
            $complexNumber = substr($complexNumber, 1);
        }
        if ($complexNumber[0] == '.') {
            $complexNumber = '0' . $complexNumber;
        }
        if ($complexNumber[0] == '+') {
            $complexNumber = substr($complexNumber, 1);
        }

        return $complexNumber;
    }