def compress_ints_lossless(x, *, method: str = "zstd") -> bytes:
    """Compress integer data using various compression methods.

    Args:
        x: NumPy array of integers to compress
        method: Compression method to use. One of:
            - "zstd": Zstandard compression (default)
            - "zlib": zlib compression
            - "lzma": LZMA compression
            - "simple_ans": Simple Asymmetric Numeral Systems

    Returns:
        Compressed bytes
    """
    if method == "zstd":
        import zstandard as zstd
        cctx = zstd.ZstdCompressor(level=22)
        return cctx.compress(x.tobytes())
    elif method == "zlib":
        import zlib
        return zlib.compress(x.tobytes(), level=9)
    elif method == "lzma":
        import lzma
        return lzma.compress(x.tobytes(), preset=9)
    elif method == "simple_ans":
        from simple_ans import ans_encode
        encoding = ans_encode(x)
        return encoding.bitstream + encoding.symbol_counts.tobytes() + encoding.symbol_values.tobytes()
    else:
        raise ValueError(f"Unknown method: {method}")