'Set the Instance Template for this Instance Group.  Existing VMs are
not recreated by setting a new InstanceTemplate.
:param  manager: Instance Group Manager to operate on.
:type   manager: :class:`GCEInstanceGroupManager`
:param  instancetemplate: Instance Template to set.
:type   instancetemplate: :class:`GCEInstanceTemplate`
:return:  True if successful
:rtype:   ``bool``'

def ex_instancegroupmanager_set_instancetemplate(self, manager, instancetemplate):

    req_data = {'instanceTemplate': instancetemplate.extra['selfLink']}
    request = ('/zones/%s/instanceGroupManagers/%s/setInstanceTemplate' % (manager.zone.name, manager.name))
    self.connection.async_request(request, method='POST', data=req_data)
    return True
