code: def _short_traceback(skip=3):
    
    counter, res = 0, []
    # Skipping 3 lines by default: the top (useless) and self-call.
    lines = traceback.format_exc().splitlines()[skip:]
    for l in lines:
      res.append(_shorten_file_path(l))
      if counter % 2 == 1:
        res.append('')
      counter += 1
      # If we see a LayerError, the traceback has already been processed.
      if l.startswith('LayerError'):
        # Skip 4 back except last as these are internal base-layer calls.
        res = res[:-4] + [res[-1]]
        res += lines[counter:]
        break
    return '\n'.join(res)
docs: Cleaned-up form of traceback.