code: def spancount(args):
      
      import json
  
      p = OptionParser(spancount.__doc__)
      opts, args = p.parse_args(args)
  
      if len(args) != 1:
          sys.exit(not p.print_help())
  
      fof, = args
      fp = open(fof)
      flist = [row.strip() for row in fp]
      spanCount = "spanCount"
      avgSpanBases = "avgSpanBases"
      fw = open(spanCount, "w")
      for f in flist:
          fp = open(f)
          j = json.load(fp)
          sc = j.get(spanCount, None)
          asb = j.get(avgSpanBases, None)
          print(f, asb, sc, file=fw)
          fw.flush()
      fw.close()
docs: %prog spancount list_of_fillingMetrics
  
      Count span support for each gap. A file with paths of all fillingMetrics can
      be built with Linux `find`.
  
      $ (find assembly -name "fillingMetrics.json" -print > list_of_fillMetrics 2>
      /dev/null &)