This method is used in with connection to REST API. It basically
        converts all important properties to dictionary, which may be used by
        frontend.

        Returns:
            dict: ``{"all_set": bool, "progress": [int(done), int(how_many)], \
                  "values": {"property": [values], ..}}``

def to_dict(self):
        """
        This method is used in with connection to REST API. It basically
        converts all important properties to dictionary, which may be used by
        frontend.

        Returns:
            dict: ``{"all_set": bool, "progress": [int(done), int(how_many)], \
                  "values": {"property": [values], ..}}``
        """
        return {
            "all_set": self._is_all_set(),
            "progress": self.progress(),
            "values": {
                property_name: getattr(self, property_name) or []
                for property_name in worker_mapping().keys()
            }
        }