import datasets
from transformers import AutoTokenizer

dataset = datasets.load_dataset(  # <1>
    "rotten_tomatoes",  # <1>
    split="train",  # <1>
)  # <1>
tokenizer = AutoTokenizer.from_pretrained("bert-base-cased")

dataset = datasets.map(  # <2>
    lambda examples: tokenizer(examples["text"]),  # <2>
    batched=True,  # <2>
)  # <2>

... # <3>