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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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()
            }
        }