private function fullDiff() : DateInterval
    {
        if (null === $this->fullDiff) {
            $this->fullDiff = $this->from->diff($this->until);
        }
        
        return $this->fullDiff;
    }
private function fullDiff() : DateInterval
    {
        if (null === $this->fullDiff) {
            $this->fullDiff = $this->from->diff($this->until);
        }
        
        return $this->fullDiff;
    }
private function fullDiff ( ) : DateInterval { if ( null === $ this -> fullDiff ) { $ this -> fullDiff = $ this -> from -> diff ( $ this -> until ) ; } return $ this -> fullDiff ; }
A full diff between the two dates.

@return DateInterval
A full diff between the two dates .