def fis_gbellmf(x:float, a:float, b:float, c:float):
    """Generalized Bell Member Function"""
    t = (x - c) / a
    if (t == 0) and (b == 0):
        return 0.5
    if (t == 0) and (b < 0):
        return 0
    return (1.0 / (1.0 + (t ** b)))