src/Interval.php
public function start(Carbon $date = null)
    {
        if (isset($date)) {
            $date->hour = 0;
            $date->minute = 0;
            $date->second = 0;

            $this->start = $date;

            return $this;
        } else {
            return $this->start;
        }
    }
public function start(Carbon $date = null)
    {
        if (isset($date)) {
            $date->hour = 0;
            $date->minute = 0;
            $date->second = 0;

            $this->start = $date;

            return $this;
        } else {
            return $this->start;
        }
    }
public function start ( Carbon $ date = null ) { if ( isset ( $ date ) ) { $ date -> hour = 0 ; $ date -> minute = 0 ; $ date -> second = 0 ; $ this -> start = $ date ; return $ this ; } else { return $ this -> start ; } }
Set or get the start date of the interval

@param Carbon|null $date
@return $this|Carbon
Set or get the start date of the interval