Lomb Scargle and False Alarm Probability

Hi

Does anyone know why if I restrict the frequency range, the false alarm probability doesn’t get computed?

ls = LombScargle(time, flux, fluxe)
prob = ls.false_alarm_probability(power[np.argmax(power)])
print(prob)
9.6467383173114e-239
ls = LombScargle(time, flux, fluxe).autopower(minimum_frequency=0.1, maximum_frequency=10)
prob = ls.false_alarm_probability(power[np.argmax(power)])
Traceback (most recent call last):
File “”, line 1, in
AttributeError: ‘tuple’ object has no attribute ‘false_alarm_probability’

many thanks
Gavin