Why use "train_data" while validating?

[jaelgu]

As line120 in train.py:

for x in tqdm(train_data, desc='train data', ncols=80):

Why do you use train data here?

[stdio2016]

Because I used training music for dummy database during testing.
I consider the case that we add songs after we train our model. In this case, the training data is already in database, and we want to know the accuracy of new songs.