public function _quote($str)
	{
		// Check that the current value is a string,
		// and is not already quoted before quoting
		// that value, otherwise, return the original value
		return (
			\is_string($str)
			&& strpos($str, $this->escapeCharOpen) !== 0
			&& strrpos($str, $this->escapeCharClose) !== 0
		)
			? "{$this->escapeCharOpen}{$str}{$this->escapeCharClose}"
			: $str;

	}