code: def pairwise(iterable):
      # from itertool recipies
      # is -> (s0,s1), (s1,s2), (s2, s3), ...
      a, b = tee(iterable)
      next(b, None)
      return zip(a, b)
  
file_path: word_cloud/wordcloud/tokenization.py
imports: from __future__ import division
  from itertools import tee
  from operator import itemgetter
  from collections import defaultdict
  from math import log
label_desc: Use image node_id 3 for calling a global function with example usage: pairwise(iterable) and returns: zip