For example, the BERT model builds its two sequence input as such: thon [CLS] SEQUENCE_A [SEP] SEQUENCE_B [SEP] We can use our tokenizer to automatically generate such a sentence by passing the two sequences to tokenizer as two arguments (and not a list, like before) like this: thon from transformers import BertTokenizer tokenizer = BertTokenizer.from_pretrained("google-bert/bert-base-cased") sequence_a = "HuggingFace is based in NYC" sequence_b = "Where is HuggingFace based?"