Attempts to load spectrum as one of the supported types.

    Returns:
        a Spectrum, or None

def load_spectrum(filename):
    """
    Attempts to load spectrum as one of the supported types.

    Returns:
        a Spectrum, or None
    """
    import f311

    f = load_with_classes(filename, f311.classes_sp())
    if f:
        return f.spectrum
    return None