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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 sync_skills_data(self):
 """ Update internal skill_data_structure from disk. """

        self.skills_data = self.load_skills_data()
        if 'upgraded' in self.skills_data:
            self.skills_data.pop('upgraded')
        else:
            self.skills_data_hash = skills_data_hash(self.skills_data)