code: def normalizer(self, maxweight, top_total):
      if not self.collection_total:
          return maxweight
      f = maxweight * self.N / self.collection_total
      return maxweight * log((1.0 + f) / f, 2) + log(1.0 + f, 2)
  
imports: from __future__ import division
  import random
  from collections import defaultdict
  from math import log
  from whoosh.compat import xrange, iteritems
label_desc: Use image node_id 1 for calling the Bo2Model obj's underlying member method code with example usage: obj.normalizer(maxweight, top_total) and returns: unknown, maxweight