How to determine train, test iteration and vocab?

Hi everyone.

I want to fit this code with my personal dataset. Not the IMDB ones. The load_data_imdb() returns 3 parameters.
To fit my dataset in, I’ve to set the 3 parameters right? But what value should I put?

Reference: 13.8. Text Classification and Data Sets — Dive into Deep Learning 0.7 documentation

from torch import nn
from d2l import torch as d2l

batch_size = 64

train_iter, test_iter, vocab = d2l.load_data_imdb(batch_size)