docs: def compute_enriched_threshold(average_window_readcount):
      # type: (float) -> int
      """
      Computes the minimum number of tags required in window for an island to be enriched.
      """
  
      current_threshold, survival_function = 0, 1
      for current_threshold in count(start=0, step=1):
          survival_function -= poisson.pmf(current_threshold,
                                           average_window_readcount)
          if survival_function <= WINDOW_P_VALUE:
              break
  
      island_enriched_threshold = current_threshold + 1
  
      return island_enriched_threshold