DenseIntElementsAttr::iterator it = kattr.begin();
    (*k)[0] = (*it).getSExtValue();
    it++;
    if (it == kattr.end()) {
      // Handle input like e.g. "k = 5", in which case we extract a single
      // diagonal.
      (*k)[1] = (*k)[0];
    } else {
      // Handle input like e.g. "k = [-1, 1]", in which case we extract a
      // band (multiple diagonals).
      (*k)[1] = (*it).getSExtValue();
    }