src/transformers/models/deberta_v2/tokenization_deberta_v2.py/SPMTokenizer/tokenize
class SPMTokenizer:    def tokenize(self, text):
        pieces = self._encode_as_pieces(text)

        def _norm(x):
            if x not in self.vocab or x == "<unk>":
                return "[UNK]"
            else:
                return x

        pieces = [_norm(p) for p in pieces]
        return pieces