public function rewind()
    {
        if ($this->datespan instanceof Day) {
            $this->current = $this->datespan;
        } else {
            $this->current = new Day($this->datespan->start());
        }
    }
public function rewind()
    {
        if ($this->datespan instanceof Day) {
            $this->current = $this->datespan;
        } else {
            $this->current = new Day($this->datespan->start());
        }
    }
public function rewind ( ) { if ( $ this -> datespan instanceof Day ) { $ this -> current = $ this -> datespan ; } else { $ this -> current = new Day ( $ this -> datespan -> start ( ) ) ; } }
returns iteration back to first day of datespan
returns iteration back to first day of datespan