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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 day_of_week(self, abbr: bool = False) -> str: """Get a random day of week. :param abbr: Abbreviated day name. :return: Day of the week. """

        key = 'abbr' if abbr else 'name'
        days = self._data['day'].get(key)
        return self.random.choice(days)