AdamWathan\Form\Elements\Date::value PHP Method

    public function value($value)
    {
        if ($value instanceof \DateTime) {
            $value = $value->format('Y-m-d');
        }
        return parent::value($value);
    }

 public function date($name)
 {
     $date = new Date($name);
     if (!is_null($value = $this->getValueFor($name))) {
         $date->value($value);
     }
     return $date;
 }