docs: def get_blocks(self, chrom, start, end):
      """
      Get any blocks in this alignment that overlap the given location.
  
      :return: the alignment blocks that overlap a given genomic interval;
               potentially none, in which case the empty list is returned.
      """
      if chrom not in self.block_trees:
        return []
      return self.block_trees[chrom].intersectingInterval(start, end)