protected function whereInSub($column, Closure $callback, $boolean, $not)
{
$type = $not ? 'NotInSub' : 'InSub';
// To create the exists sub-select, we will actually create a query and call the
// provided callback with the query so the developer may set any of the query
// conditions they want for the in clause, then we'll put it in this array.
call_user_func($callback, $query = $this->newQuery());
$this->wheres[] = compact('type', 'column', 'query', 'boolean');
$this->addBinding($query->getBindings(), 'where');
return $this;
}