public function toHash(SPIValue $value)
{
if ($this->isEmptyValue($value)) {
return null;
}
if ($value->date instanceof DateTime) {
return array('timestamp' => $value->date->getTimestamp(), 'rfc850' => $value->date->format(DateTime::RFC850));
}
return array('timestamp' => 0, 'rfc850' => null);
}