docs: def range(self):
      """Return the range the transcript loci covers
  
      :return: range
      :rtype: GenomicRange
      """
      chrs = set([x.range.chr for x in self.get_transcripts()])
      if len(chrs) != 1: return None
      start = min([x.range.start for x in self.get_transcripts()])
      end = max([x.range.end for x in self.get_transcripts()])
      return GenomicRange(list(chrs)[0],start,end)