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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 load_from_store(self):
 """Load index from store. :return: Whether index was correctly loaded or not :rtype: bool :raise AttributeError: If no datastore is defined """

        if not self._store:
            raise AttributeError('No datastore defined!')
        if self._store.has_blob('all_keys'):
            data = Serializer.deserialize(self._store.get_blob('all_keys'))
            self.load_from_data(data)
            return True
        elif self._store.has_blob('all_keys_with_undefined'):
            blob = self._store.get_blob('all_keys_with_undefined')
            data = Serializer.deserialize(blob)
            self.load_from_data(data, with_undefined=True)
            return True
        else:
            return False