public function related($name, $value)
{
if (!isset($this->_fields[$name]) or !$this->_fields[$name] instanceof Sprig_Field_HasMany) {
throw new Sprig_Exception('Unknown relationship: :name', array(':name' => $name));
}
// Make sure the field is accessed to load it's values
$this->{$name};
return in_array($value, $this->_original[$name]);
}