docs: def cmp(self,range2,overlap_size=0):
      """the comparitor for ranges
  
       * return 1 if greater than range2
       * return -1 if less than range2
       * return 0 if overlapped
  
      :param range2:
      :param overlap_size: allow some padding for an 'equal' comparison (default 0)
      :type range2: GenomicRange
      :type overlap_size: int
  
      """
      if self.overlaps(range2,padding=overlap_size): return 0
      if self.chr < range2.chr: return -1
      elif self.chr > range2.chr: return 1
      elif self.end < range2.start: return -1
      elif self.start > range2.end: return 1
      sys.stderr.write("ERROR: cmp function unexpcted state\n")
      sys.exit()
      return 0