public function removeNamedRange($namedRange, Worksheet $pSheet = null)
    {
        if ($pSheet === null) {
            if (isset($this->namedRanges[$namedRange])) {
                unset($this->namedRanges[$namedRange]);
            }
        } else {
            if (isset($this->namedRanges[$pSheet->getTitle() . '!' . $namedRange])) {
                unset($this->namedRanges[$pSheet->getTitle() . '!' . $namedRange]);
            }
        }

        return $this;
    }