public function add(string $class, string $filename): self
    {
        $this->appClasses->add($class, $this->dir . '/' . $filename);
        return $this;
    }
public function add(string $class, string $filename): self
    {
        $this->appClasses->add($class, $this->dir . '/' . $filename);
        return $this;
    }
public function add ( string $ class , string $ filename ) : self { $ this -> appClasses -> add ( $ class , $ this -> dir . '/' . $ filename ) ; return $ this ; }
Registers a class for autoloading in the current context.

@param string $class The class name or class name pattern (format: Namespace\*).
@param string $filename The filename that contains the class or path pattern (format: path/to/file/*.php).
@return self Returns a reference to itself.
Registers a class for autoloading in the current context .