def METHOD_NAME(ovs):
    domxml = minidom.parseString("""<?xml version="1.0" encoding="utf-8"?>
    <interface type="bridge">
        <mac address="00:1a:4a:16:01:51"/>
        <model type="virtio"/>
        <source bridge="sample_network"/>
    </interface>""")
    if ovs:
        pluginType = PT_OVS
    else:
        pluginType = PT_BRIDGE
    import openstacknet_utils
    openstacknet_utils.executeOrExit = openstacknet_utils.mockExecuteOrExit
    addOpenstackVnic(domxml,
                     pluginType,
                     'test_port_id')
    print(domxml.toxml(encoding='utf-8'))