/**
* Return the "casting helper" (a piece of PHP code that when evaluated creates a casted value object) for a field
* on this object.
*
* @param string $field
* @return string
*/
public function castingHelper($field)
{
if ($this->copyContentFrom()) {
return $this->copyContentFrom()->castingHelper($field);
} else {
return parent::castingHelper($field);
}
}
