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)