AttributeError: type object 'Attack' has no attribute 'sample_device_choices'

db = bob.db.replaymobile.Database()
db.attack_sampling_devices()
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-8-9be7b1aeccd8> in <module>()
----> 1 db.attack_sampling_devices()

/home/amir/idiap/git/bobs/bob.bio.face/src/bob.db.replaymobile/bob/db/replaymobile/query.py in attack_sampling_devices(self)
    304     """Returns sampling devices available in the database"""
    305 
--> 306     return Attack.sample_device_choices
    307 
    308   def attack_sample_types(self):

AttributeError: type object 'Attack' has no attribute 'sample_device_choices'