crash

[ValkAcadamer]

python pret.py
Traceback (most recent call last):
File "pret.py", line 8, in
from discovery import discovery
File "/opt/PRET/discovery.py", line 13, in
from pysnmp.proto import api
File "/usr/lib/python2.7/dist-packages/pysnmp/proto/api/init.py", line 7, in
from pysnmp.proto.api import v1, v2c, verdec
File "/usr/lib/python2.7/dist-packages/pysnmp/proto/api/v1.py", line 8, in
from pysnmp.proto import rfc1155, rfc1157, error
File "/usr/lib/python2.7/dist-packages/pysnmp/proto/rfc1155.py", line 50, in
class NetworkAddress(univ.Choice):
File "/usr/lib/python2.7/dist-packages/pysnmp/proto/rfc1155.py", line 55, in NetworkAddress
def clone(self, value=univ.noValue, **kwargs):
AttributeError: 'module' object has no attribute 'noValue'

hi
I have installed the depend