Haven't tried it myself, but look at the "metrocluster-switchover" in the NetApp SDK documentation. I guess something like this should work:
import NaServer, NaElement
hostname = ''
username = ''
password = ''
zapi = SDK.NaServer(hostname, 1, 3)
zapi.set_server_type('FILER')
zapi.set_transport_type('HTTPS')
zapi.set_style('LOGIN')
zapi.set_admin_user(username, password)
request = SDK.NaElement('metrocluster-switchover')
request.child_add_string('simulate', 'true')
response = zapi.invoke_elem(request)
This should simulate a switchover, but I warn again: haven't tried it myself.