code: def init(self):
          
          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()
docs: 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.