public function gap(Period $period)
	    {
	        if ($this->overlaps($period)) {
	            throw new LogicException('Both Period objects should not overlaps');
	        }

	        if ($period->start > $this->start) {
	            return new self($this->end, $period->start);
	        }

	        return new self($period->end, $this->start);
	    }