class_docstr: Defines a dataset for machine translation.
class_docstr_tok: ["Defines","a","dataset","for","machine","translation","."]
code: def sort_key(ex):
      return data.interleave_keys(len(ex.src), len(ex.trg))
  
file_path: pytext/pytext/legacy/datasets/translation.py
imports: import os
  import codecs
  import glob
  import io
  from ..None import data
label_desc: Use image node_id 1 for calling the TranslationDataset obj's underlying member method code with example usage: obj.sort_key(ex) and returns: data