def calcdd(self, t):
    '\n        Calc second derivative\n        '
    if (t < self.x[0]):
        return None
    elif (t > self.x[(- 1)]):
        return None
    i = self.__search_index(t)
    dx = (t - self.x[i])
    result = ((2.0 * self.c[i]) + ((6.0 * self.d[i]) * dx))
    return result
Calc second derivative
def calcdd(self, t):
    '\n        \n        '
    if (t < self.x[0]):
        return None
    elif (t > self.x[(- 1)]):
        return None
    i = self.__search_index(t)
    dx = (t - self.x[i])
    result = ((2.0 * self.c[i]) + ((6.0 * self.d[i]) * dx))
    return result