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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 execute(self):
 """ Executes the actor. :return: None if successful, otherwise error message :rtype: str """

        if self.skip:
            return None

        result = self.pre_execute()
        if result is None:
            try:
                result = self.do_execute()
            except Exception as e:
                result = traceback.format_exc()
                print(self.full_name + "\n" + result)
        if result is None:
            result = self.post_execute()
        return result