Expected combineable dataset

[s1530129650]

I download tensorflow from https://polybox.ethz.ch/index.php/s/ojd0RPFOtUTPPRr and put tensorflow/ir_0 in data/.
When i run python train_inst2vec.py, there is a error :
"Expected combineable dataset"

I know the except is from https://github.com/spcl/ncc/blob/master/inst2vec/inst2vec_embedding.py#L56. However, I don't know why single file is not allowed? I just would like to quickly run the code and get some result, so i put a single file in /data.
Please tell me why it is wrong to put a single file in /data

error info

python-BaseException
Traceback (most recent call last):
File "3\envs\ncc\lib\site-packages\absl\app.py", line 274, in run
_run_main(main, args)
File "\Anaconda3\envs\ncc\lib\site-packages\absl\app.py", line 238, in _run_main
sys.exit(main(argv))
File "/ncc/train_inst2vec.py", line 60, in main
embedding_matrix, embeddings_file = i2v_emb.train_embeddings(data_folder, data_folders)
File "\ncc\inst2vec\inst2vec_embedding.py", line 453, in train_embeddings
data_pair_files = get_data_pair_files(data_folders, context_width)
File "\ncc\inst2vec\inst2vec_embedding.py", line 56, in get_data_pair_files
assert len(folders) > 1, "Expected combineable dataset"
AssertionError: Expected combineable dataset

Process finished with exit code 1

[tbennun]

@s1530129650 That should be fine. Does anything strange happen if you comment out that line?