system/Database/BaseBuilder.php
public function whereNotIn(string $key = null, array $values = null, bool $escape = null)
	{
		return $this->_whereIn($key, $values, true, 'AND ', $escape);
	}
public function whereNotIn(string $key = null, array $values = null, bool $escape = null)
	{
		return $this->_whereIn($key, $values, true, 'AND ', $escape);
	}
WHERE NOT IN

Generates a WHERE field NOT IN('item', 'item') SQL query,
joined with 'AND' if appropriate.

@param string  $key    The field to search
@param array   $values The values searched on
@param boolean $escape

@return BaseBuilder