code: def multinomLog2(selectors):
      
  
      ln2 = 0.69314718055994528622
      noAll = sum(selectors)
      lgNf = math.lgamma(noAll + 1.0) / ln2  # log2(N!)
  
      lgnFac = []
      for selector in selectors:
          if selector == 0 or selector == 1:
              lgnFac.append(0.0)
          elif selector == 2:
              lgnFac.append(1.0)
          elif selector == noAll:
              lgnFac.append(lgNf)
          else:
              lgnFac.append(math.lgamma(selector + 1.0) / ln2)
      return lgNf - sum(lgnFac)
docs: Function calculates logarithm 2 of a kind of multinom.
  
      selectors: list of integers