code: def _target_encoder(self):
      pass
  
imports: import tensorflow
  from tensorflow import TensorShape
  import numpy
  from finetune.errors import FinetuneError
  from finetune.base import PredictMode, BaseModel
  from finetune.base_models import RoBERTa, BERT
  from finetune.input_pipeline import BasePipeline
  from finetune.nn.target_blocks import masked_language_model
label_desc: Use image node_id 1 for calling the MaskedLanguageModelPipeline obj's underlying member method code with example usage: obj._target_encoder() without return types