Is it a bug not to eliminate first element of a line in `tag-item.dat` ?

[horiken4]

tag-item.dat has number of tags related to an article at first element of any line.
So i think when counting number of tags first element should be eliminated.
But utils.py seems to regard the first element as a tag according to below code.

CollMetric/utils.py

Line 29 in d9026cf

if len(items) >= tag_occurence_thres:

CollMetric/utils.py

Line 37 in d9026cf

features[[int(i) for i in items], feature_index] = 1

Is it a bug or do I have any misunderstanding?