code: def preprocess(self, x):
      if isinstance(x, list):
          return [super(BABI20Field, self).preprocess(s) for s in x]
      else:
          return super(BABI20Field, self).preprocess(x)
  
file_path: pytext/pytext/legacy/datasets/babi.py
imports: import os
  from io import open
  import torch
  from ..data import Dataset, Example, Field, Iterator
label_desc: Use image node_id 2 for calling the BABI20Field obj's underlying member method code with example usage: obj.preprocess(x) and returns: unknown, super