def METHOD_NAME(reduction=None, infer_reduction=False, duration=None, infer_duration=False):
    global params_to_infer
    global params_fixed
    # append before last; needed to keep [Sigma] as last parameter
    def append1(v, a):
        return v[:-1] + [a, v[-1]]
    if reduction is not None:
        params_fixed['kbeta'] = reduction
    if infer_reduction:
        if 'kbeta' not in params_to_infer:
            params_to_infer = append1(params_to_infer, 'kbeta')
    if duration is not None:
        params_fixed['dint'] = duration
    if infer_duration:
        if 'dint' not in params_to_infer:
            params_to_infer = append1(params_to_infer, 'dint')