Failed to save PHP objects in mongodb

Obtaining "keys of zero length is not allowed" FATAL error while saving the object.

Is this due to the presence of __construct ()?

I believe the PHP object is resolved in the save () method.

class Address{
    private $name;
    private $company;
    private $zip;

    public function __construct($name,$company,$zip){
        $this->name = $name;
        $this->company = $company;
        $this->zip = $zip;
    }
}

$newAddress = new Address("james","google",678);

print_r($newAddress);
// Address Object ( [name:Address:private] => james [company:Address:private] =>
// google [zip:Address:private] => 678 )

$addresses->save($newAddress);    

      

        
        
        
      

    

Fatal error: uncaught "MongoException" with message "zero-length keys" is invalid, did you use $ with double quotes? "in /var/www/html/index.php:105 Stack trace: # 0 / var / www / html / index.php (105): MongoCollection-> save (Object (Address)) # 1 {main} throw in /var/www/html/index.php on line 105