def verify_fft_options(opt, parser):
    """Parses the FFT options and verifies that they are
       reasonable.

    Parameters
    ----------
    opt : object
        Result of parsing the CLI with OptionParser, or any object with the
        required attributes.
    parser : object
        OptionParser instance.
    """

    if len(opt.fft_backends) > 0:
        _all_backends = get_backend_names()
        for backend in opt.fft_backends:
            if backend not in _all_backends:
                parser.error("Backend {0} is not available".format(backend))

    for backend in get_backend_modules():
        try:
            backend.verify_fft_options(opt, parser)
        except AttributeError:
            pass
Parses the FFT options and verifies that they are
       reasonable.

    Parameters
    ----------
    opt : object
        Result of parsing the CLI with OptionParser, or any object with the
        required attributes.
    parser : object
        OptionParser instance.