public function getPrevious()
    {
        $start = clone $this->begin;
        $start->sub(static::getDateInterval());

        return new static($start, $this->factory);
    }
public function getPrevious()
    {
        $start = clone $this->begin;
        $start->sub(static::getDateInterval());

        return new static($start, $this->factory);
    }
public function getPrevious ( ) { $ start = clone $ this -> begin ; $ start -> sub ( static :: getDateInterval ( ) ) ; return new static ( $ start , $ this -> factory ) ; }
Gets the previous period of the same type.

@return PeriodInterface
Gets the previous period of the same type .