public function setSortable($sortable = true)
	{
		$this->sortable = is_string($sortable) ? $sortable : (bool) $sortable;

		return $this;
	}
public function setSortable($sortable = true)
	{
		$this->sortable = is_string($sortable) ? $sortable : (bool) $sortable;

		return $this;
	}
public function setSortable ( $ sortable = true ) { $ this -> sortable = is_string ( $ sortable ) ? $ sortable : ( bool ) $ sortable ; return $ this ; }
Set column sortable or not
@param bool|string $sortable
Set column sortable or not