F5 Python SDK: How to get virtual server availability?

I'm also struggling with this:

partition  = 'C25'
pool_name = 'temp_test'
 {u'https://localhost/mgmt/tm/ltm/pool/~C25~temp_test/~C25~temp_test/stats': {u'nestedStats': {u'entries': {u'activeMemberCnt': {u'value': 1},
pool  = mgmt.tm.ltm.pools.pool.load(name=pool_name, partition=partition)
stats = pool.stats.load()
print("{}".format(pformat(stats.entries)))

selflink = "https://{0}/mgmt/tm/ltm/pool/~{1}~{2}/~{1}~{2}/stats".format(bigip,partition,pool_name)

slink   = stats.entries.get(selflink)
nested  = slink.get('nestedStats')
entries = nested.get('entries')

activeMemberCnt = entries.get('activeMemberCnt').get('value')

Output:

Traceback (most recent call last):
  File "test_f5.py", line 46, in 
    nested  = slink.get('nestedStats')
AttributeError: 'NoneType' object has no attribute 'get'

So, using the example above, I am not able to get the selflink, but I have created the selflink string from what's given in the raw output. I'm working against: BIG-IP 12.1.3 Build 0.0.378 Final