code: def select_bed(bed):
      
      ranges = [Range(x.seqid, x.start, x.end, float(x.score), i) for i, x in enumerate(bed)]
      selected, score = range_chain(ranges)
      selected = [bed[x.id] for x in selected]
  
      return selected
docs: Return non-overlapping set of ranges, choosing high scoring blocks over low
      scoring alignments when there are conflicts.