code: def _get_ref_lengths(self):
          '''Gets the length of each reference sequence from the header of the bam. Returns dict name => length'''
          sam_reader = pysam.Samfile(self.bam, "rb")
          return dict(zip(sam_reader.references, sam_reader.lengths)f _get_ref_lengths(self):
          '''Gets the length of each reference sequence from the header of the bam. Returns dict name => length'''
          sam_reader = pysam.Samfile(self.bam, "rb")
          return dict(zip(sam_reader.references, sam_reader.lengths))
docs: Gets the length of each reference sequence from the header of the bam. Returns dict name => length