public function Start()
    {
        if(!file_exists($this->definitions_path))
        {
            throw new \Exception(
                t("Trying to import symbols from a non existent directory.")
            );
        }
        
        $this->SendMessage(
            sprintf(
                t("Starting import of definitions stored in %s format."),
                $this->import_type
            )
        );
        
        if($this->import_type == Type::JSON)
        {
            $this->LoadFromJSON($this->definitions_path);
        }
        else
        {
            $this->LoadFromPHP($this->definitions_path);
        }
        
        $this->SendMessage(t("Import completed."));
    }