public function setEncoding($encoding)
	{
		if ( ! is_string($encoding) || ! in_array($encoding, mb_list_encodings())) {
			throw new \InvalidArgumentException(
				__METHOD__."() expects parameter one, encoding, to be a valid "
				 . "character encoding name"
			);
		}
		
		$this->encoding = $encoding;
		
		return $this;
	}