public static function firstWeekOfYear($year = null)
    {
        $year = $year ? (int) $year : Date('Y');
        return Carbon::parse($year . '-01-01')->startOfWeek(Carbon::SUNDAY);
    }
public static function firstWeekOfYear($year = null)
    {
        $year = $year ? (int) $year : Date('Y');
        return Carbon::parse($year . '-01-01')->startOfWeek(Carbon::SUNDAY);
    }
public static function firstWeekOfYear ( $ year = null ) { $ year = $ year ? ( int ) $ year : Date ( 'Y' ) ; return Carbon :: parse ( $ year . '-01-01' ) -> startOfWeek ( Carbon :: SUNDAY ) ; }
Determine the first week of the given year.

@param  int $year
@return Isotope
Determine the first week of the given year .