How to get the wordnet sense frequency of a synset in NLTK?

I managed to do it this way.

from nltk.corpus import wordnet as wn

word = "dog"
synsets = wn.synsets(word)

sense2freq = {}
for s in synsets:
  freq = 0  
  for lemma in s.lemmas:
    freq+=lemma.count()
  sense2freq[s.offset+"-"+s.pos] = freq

for s in sense2freq:
  print s, sense2freq[s]