protected function replaceQuantifierByKey($key, $replacement = '')
	{
		$subject = $this->pattern[$key];

		if (strripos($subject, ')') !== false)
		{
			$subject             = rtrim($subject, ')');
			$subject             = $this->removeQuantifier($subject);
			$this->pattern[$key] = sprintf('%s%s)', $subject, $replacement);
		}
		else
		{
			$subject             = $this->removeQuantifier($subject);
			$this->pattern[$key] = sprintf('%s%s', $subject, $replacement);
		}

		return $this;
	}