code: def sentence_position(i, size):
      
  
      normalized = i*1.0 / size
      if 0 < normalized <= 0.1:
          return 0.17
      elif 0.1 < normalized <= 0.2:
          return 0.23
      elif 0.2 < normalized <= 0.3:
          return 0.14
      elif 0.3 < normalized <= 0.4:
          return 0.08
      elif 0.4 < normalized <= 0.5:
          return 0.05
      elif 0.5 < normalized <= 0.6:
          return 0.04
      elif 0.6 < normalized <= 0.7:
          return 0.06
      elif 0.7 < normalized <= 0.8:
          return 0.04
      elif 0.8 < normalized <= 0.9:
          return 0.04
      elif 0.9 < normalized <= 1.0:
          return 0.15
      else:
          return 0
docs: different sentence positions indicate different
      probability of being an important sentence