As a python snippet, attaching a network looks like this:

hosts_service = connection.system_service().hosts_service()
host = hosts_service.list(search='name=ovirt-node-ng-image-20190129-1')[0]
host_service = hosts_service.host_service(host.id)
host_service.setup_networks(
    modified_network_attachments=[
        types.NetworkAttachment(
            network=types.Network(
                name='ovirtmgmt',
            ),
            host_nic=types.HostNic(
                name='eth0',
            ),
            ip_address_assignments=[
                types.IpAddressAssignment(
                    assignment_method=types.BootProtocol.STATIC,
                    ip=types.Ip(
                        address='192.168.122.22',
                        netmask='255.255.255.0',
                        gateway='192.168.122.1'
                    ),
                ),
            ],
        ),
    ]
)

Please find the documentation in