def METHOD_NAME():
    """Sets up the look-up tables for levels as a function of input byte.
    Returns
    -------
    lut1bit, lut2bit, lut4but : `~numpy.ndarray`
        Look-up table for decoding bytes to samples of 1, 2, and 4 bits, resp.
    Notes
    -----
    Look-up tables are two-dimensional arrays whose first axis is indexed
    by byte value (in uint8 form) and whose second axis represents sample
    temporal order.  Table values are decoded sample values.  Sec. 10 in
    the `VDIF Specification
    <https://vlbi.org/wp-content/uploads/2019/03/VDIF_specification_Release_1.1.1.pdf>`_
    states that samples are encoded by offset-binary, such that all 0
    bits is lowest and all 1 bits is highest.  I.e., for 2-bit sampling,
    the order is 00, 01, 10, 11.  These are decoded using
    `~baseband.base.encoding.decoder_levels`.
    For example, the 2-bit sample sequence ``-1, -1, 1, 1`` is encoded
    as ``0b10100101`` (or ``165`` in uint8 form).  To translate this back
    to sample values, access ``lut2bit`` using the byte as the key::
        >>> lut2bit[0b10100101]
        array([-1., -1.,  1.,  1.], dtype=float32)
    """
    b = np.arange(256)[:, np.newaxis]
    # 1-bit mode
    i = np.arange(8)
    lut1bit = decoder_levels[1][(b >> i) & 1]
    # 2-bit mode
    i = np.arange(0, 8, 2)
    lut2bit = decoder_levels[2][(b >> i) & 3]
    # 4-bit mode
    i = np.arange(0, 8, 4)
    lut4bit = decoder_levels[4][(b >> i) & 0xf]
    return lut1bit, lut2bit, lut4bit