Entity/AccompanyingPeriod.php
public function isClosingAfterOpening() {
        $diff = $this->getOpeningDate()->diff($this->getClosingDate());
        
        if ($diff->invert === 0) {
            return true;
        } else {
            return false;
        }
    }
public function isClosingAfterOpening() {
        $diff = $this->getOpeningDate()->diff($this->getClosingDate());
        
        if ($diff->invert === 0) {
            return true;
        } else {
            return false;
        }
    }
Returns true if the closing date is after the opening date.

@return boolean