code: def __init__(self, cfg):
      if cfg.bpe_codes is None:
          raise ValueError("--bpe-codes is required for --bpe=fastbpe")
      codes = file_utils.cached_path(cfg.bpe_codes)
      try:
          import fastBPE
  
          self.bpe = fastBPE.fastBPE(codes)
          self.bpe_symbol = "@@ "
      except ImportError:
          raise ImportError(
              "Please install fastBPE with: pip install fastBPE"
          )
  
file_path: fairseq/fairseq/data/encoders/fastbpe.py
imports: from dataclasses import dataclass, field
  from fairseq import file_utils
  from fairseq.data.encoders import register_bpe
  from fairseq.dataclass import FairseqDataclass
label_desc: Use image node_id 1 to create a new fastBPE object from inherited base classes: object with example: obj = fastBPE(cfg)