'Deduce PortFixture class from bridge type and instantiate it.'

@classmethod
def get(cls, bridge, namespace=None, mac=None, port_id=None, hybrid_plug=False):

    if isinstance(bridge, ovs_lib.OVSBridge):
        return OVSPortFixture(bridge, namespace, mac, port_id, hybrid_plug)
    if isinstance(bridge, bridge_lib.BridgeDevice):
        return LinuxBridgePortFixture(bridge, namespace, mac, port_id)
    if isinstance(bridge, VethBridge):
        return VethPortFixture(bridge, namespace)
    tools.fail(('Unexpected    bridge    type:    %s' % type(bridge)))
