problems with the connection script to a nessus server

I'm trying to connect to a nessus server using the library that nessus makes available .... however, there are several errors and warnings reported by the terminal:

enter image description here

from pynessus import Nessus
from pynessus.models.user import User
from pynessus.models.policy import Policy

server=Nessus("localhost", 8834)

 [enter image description here][2]if server.login(User("username", "password")):
 server.load_policies()
 # display available policies
 for policy in server.policies:
     print ("%s - %s" % (policy.db_id, policy.name))

 # creating a policy
 p = server.Policy()
 p.name = "My new policy"
 if p.save():
     print ("[+] Policy %s successfully created." % p.name)
 else:
     print ("[!] An error occured while creating policy %s" % p.name)

 # updating a policy
 p.description = "Let's set a description."
 if p.save():
     print ("[+] Policy %s successfully updated." % p.name)
 else:
     print ("[!] An error occured while updating policy %s" % p.name)

 # downloading nessus xml policy description#
 path =  p.download()


 if path is not None:
     print ("[+] Policy %s successfully downloaded to %s." % (p.name, path))
 else:
     print ("[!] An error occured while downloading policy %s" % p.name)

 # deleting a policy
 if p.delete():
     print ("[+] Policy %s successfully deleted." % p.name)
 else:
     print ("[!] An error occured while deleting policy %s" % p.name)
 else:
 print ("Fail!")