docs/examples/loadbalancer/elb/ex_set_balancer_policies_backend_server.py

from libcloud.loadbalancer.types import Provider
from libcloud.loadbalancer.providers import get_driver

ACCESS_ID = "your access id"
SECRET_KEY = "your secret key"

cls = get_driver(Provider.ELB)
driver = cls(key=ACCESS_ID, secret=SECRET_KEY)

driver.ex_set_balancer_policies_backend_server(
    name="MyLB", port=80, policies=["MyDurationStickyPolicy"]
)