docstr: Convert source string into bpe tokens.
docstr_tok: ["Convert","source","string","into","bpe","tokens","."]
code: def tokenize(self, text: str):
      """
      Convert source string into bpe tokens.
      """
      moses_tokens = self.moses_tokenizer.tokenize(text)
      tokenized_text = " ".join(moses_tokens)
      tokenized_bpe_text = self.bpe_tokenizer.process_line(
          tokenized_text
      )  # Apply bpe to text
      bpe_tokens = tokenized_bpe_text.split(" ")
      return bpe_tokens
  
file_path: PaddleHub/modules/text/machine_translation/transformer/en-de/utils.py
imports: import re
  from typing import List
  import codecs
  from sacremoses import MosesTokenizer, MosesDetokenizer
  from subword_nmt.apply_bpe import BPE
label_desc: Use image node_id 2 for calling the MTTokenizer obj's underlying member method code with example usage: obj.tokenize(text) and returns: bpe_tokens