Error when running collaborative-dl.ipynb

Traceback:

AttributeError Traceback (most recent call last)
in ()
24 fp.close()
25
---> 26 cal_rec(1,8)

in cal_rec(p, cut)
17 l_rec = list(zip(*pl)[0])[:cut]
18 s_rec = set(l_rec)
---> 19 s_true = set(np.where(R_true[i,:]>0)[1].A1)
20 cnt_hit = len(s_rec.intersection(s_true))
21 fp.write('%d:' % cnt_hit)

AttributeError: 'numpy.ndarray' object has no attribute 'A1'

@aileli