def save_hdf5(X, y, path):
    """Save data as a HDF5 file.

    Args:
        X (numpy or scipy sparse matrix): Data matrix
        y (numpy array): Target vector.
        path (str): Path to the HDF5 file to save data.
    """

    with h5py.File(path, 'w') as f:
        is_sparse = 1 if sparse.issparse(X) else 0
        f['issparse'] = is_sparse
        f['target'] = y

        if is_sparse:
            if not sparse.isspmatrix_csr(X):
                X = X.tocsr()

            f['shape'] = np.array(X.shape)
            f['data'] = X.data
            f['indices'] = X.indices
            f['indptr'] = X.indptr
        else:
            f['data'] = X
Save data as a HDF5 file.

    Args:
        X (numpy or scipy sparse matrix): Data matrix
        y (numpy array): Target vector.
        path (str): Path to the HDF5 file to save data.