protected function isInstanceFilter($filter)
	{
		if (is_string($filter) && starts_with($filter, '@'))
		{
			if (method_exists($this, substr($filter, 1))) return true;

			throw new \InvalidArgumentException("Filter method [$filter] does not exist.");
		}

		return false;
	}
protected function isInstanceFilter($filter)
	{
		if (is_string($filter) && starts_with($filter, '@'))
		{
			if (method_exists($this, substr($filter, 1))) return true;

			throw new \InvalidArgumentException("Filter method [$filter] does not exist.");
		}

		return false;
	}
protected function isInstanceFilter ( $ filter ) { if ( is_string ( $ filter ) && starts_with ( $ filter , '@' ) ) { if ( method_exists ( $ this , substr ( $ filter , 1 ) ) ) return true ; throw new \ InvalidArgumentException ( "Filter method [$filter] does not exist." ) ; } return false ; }
Determine if a filter is a local method on the controller.

@param  mixed  $filter
@return boolean

@throws \InvalidArgumentException
Determine if a filter is a local method on the controller .