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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 init(self):
 """ Validates the given ``ovsdb_addr`` and connects to OVS instance. If failed to connect to OVS instance or the given ``datapath_id`` does not match with the Datapath ID of the connected OVS instance, raises :py:mod:`ryu.lib.ovs.bridge.OVSBridgeNotFound` exception. """

        if not valid_ovsdb_addr(self.ovsdb_addr):
            raise ValueError('Invalid OVSDB address: %s' % self.ovsdb_addr)
        if self.br_name is None:
            self.br_name = self._get_bridge_name()