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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 connection(self, connection):
 """ Change the dynamo connection """

        if connection is not None:
            connection.subscribe("capacity", self._on_capacity_data)
            connection.default_return_capacity = True
        if self._connection is not None:
            connection.unsubscribe("capacity", self._on_capacity_data)
        self._connection = connection
        self._cloudwatch_connection = None
        self.cached_descriptions = {}