def _symmetrize_matrix_and_fix_diagonal(
x_non_symmetric: csr_matrix) -> csr_matrix:
x_symmetric = x_non_symmetric.tolil()
r, c = x_symmetric.nonzero()
x_symmetric[c, r] = x_symmetric[r, c]
r = np.arange(x_symmetric.shape[0])
x_symmetric[r, r] = 1
return x_symmetric.tocsr()
