protected static function arrayMergeRecursive($array1, $array2)
	{
		if ( !is_array($array1) || !is_array($array2) ) {
			return $array2;
		}

		foreach ( $array2 as $array2_key => $array2_value ) {
			if ( isset($array1[$array2_key]) ) {
				$array1[$array2_key] = self::arrayMergeRecursive($array1[$array2_key], $array2_value);
			}
			else {
				$array1[$array2_key] = $array2_value;
			}
		}

		return $array1;
	}