def METHOD_NAME(T, k):
    """
    Fourth-order polynomial least-squares fit to data
    """
    assert len(T) > 4, 'Input lists must have at least five elements'
    assert len(T) == len(k), 'Input lists must be equal length'
    def func(T, a0, a1, a2, a3, a4):
        return a0 + a1 * T + a2 * T**2 + a3 * T**3 + a4 * T**4
    popt, pcov = curve_fit(func, T, k)
    def outputFunc(temperatures):
        return func(np.asarray(temperatures), *popt)
    return outputFunc