private function addRule($data, $ruleType)
	{
		if (\is_string($data))
		{
			$data = array($data);
		}
		elseif (!\is_array($data))
		{
			// Do not translate.
			throw new InvalidArgumentException('Invalid inflector rule data.');
		}

		foreach ($data as $rule)
		{
			// Ensure a string is pushed.
			array_push($this->rules[$ruleType], (string) $rule);
		}
	}