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.

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()