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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 get(self, key):
 """ Returns attribute value. :param key :returns value """


        if not self.is_loaded:
            self.retrieve()

            self.is_loaded = True

        if self.has(key=key):
            return self.data[key]
        else:
            return None