public function findFilter($field)
	{
		$filters = $this->getFilters();

		//return either the Field object or throw an InvalidArgumentException
		if (!isset($filters[$field]))
		{
			throw new \InvalidArgumentException("The " . $field . " filter does not exist on the " . $this->config->getOption('name') . " model");
		}

		return $filters[$field];
	}