Lauch paralel processes (see :func:`.worker`) to asynchrnously fill
        properties with data.

def paralel_processing(self):
        """
        Lauch paralel processes (see :func:`.worker`) to asynchrnously fill
        properties with data.
        """
        self._reset_set_properties()

        self.index = download(self.url)
        self.downloaded_ts = time.time()
        self.processing_started_ts = time.time()

        # launch all workers as paralel processes
        for name, function_info in worker_mapping().iteritems():
            p = Process(
                target=worker,
                kwargs={
                    "url_key": self.url,
                    "property_name": name,
                    "function": function_info.func,
                    "function_arguments": function_info.args_func(self),
                }
            )
            p.start()