code: def generate_cumulative_dist(island_expectations_d, total_length):
      # type: (Dict[int, float], int) -> float
      
  
      cumulative = [0.0] * (total_length + 1)
      partial_sum = 0.0
  
      island_expectations = []
      for i in range(len(cumulative)):
          if i in island_expectations_d:
              island_expectations.append(island_expectations_d[i])
          else:
              island_expectations.append(0)
  
      for index in range(1, len(island_expectations) + 1):
          complimentary = len(island_expectations) - index
          partial_sum += island_expectations[complimentary]
          cumulative[complimentary] = partial_sum
  
      # move to function call
      for index in range(len(cumulative)):
          if cumulative[index] <= E_VALUE:
              score_threshold = index * BIN_SIZE
              break
  
      return score_threshold
docs: Generate cumulative distribution: a list of tuples (bins, hist).