def METHOD_NAME(filename):
    """
    Checks whether a file is a audio WAV file or not.
    :type filename: str
    :param filename: Name of the audio WAV file to be checked.
    :rtype: bool
    :return: ``True`` if a WAV file.
    .. rubric:: Example
    >>> _is_wav("/path/to/3cssan.near.8.1.RNON.wav")  #doctest: +SKIP
    True
    """
    try:
        fh = wave.open(filename, 'rb')
        try:
            (_nchannel, width, _rate, _len, _comptype, _compname) = \
                fh.getparams()
        finally:
            fh.close()
    except Exception:
        return False
    if width in [1, 2, 4]:
        return True
    return False