code: def text2text_txt_tab_iterator(txt_path):
    
    for line in txt_line_iterator(txt_path):
      if line and "\t" in line:
        parts = line.split("\t", 1)
        inputs, targets = parts[:2]
        yield {"inputs": inputs.strip(), "targets": targets.strip()}
docs: Yield dicts for Text2TextProblem.generate_samples from lines of txt_path.
  
    Args:
      txt_path: path to txt file with a record per line, source and target
        are tab-separated.
  
    Yields:
      {"inputs": inputs, "targets": targets}