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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 rating(self):
 """Returns the Place's rating, from 0.0 to 5.0, based on user reviews. This method will return None for places that have no rating. """

        if self._rating == '' and self.details != None and 'rating' in self.details:
            self._rating = self.details['rating']
        return self._rating