Unresolved feedback from #278

[jnm]

@noliveleger if there are more points that I've missed, please edit this description to add them 🙂

• (1)

  Our coding habits have changed since my last review:
  We are now used to import from __future__ import annotations.
  def extend_survey(self, analysis_form: dict) -> None:
  and dict[str, str] should work too.
  Let's use the import then and change Dict to dict
  Originally posted by @noliveleger in MVP: Handle extra fields to export #278 (comment)

• (2)

  @joshuaberetta what about this:

  item = re.sub(r'^_supplementalDetails/', '', item)
  # use explicit names for variable below.
  # `_` is dummy content, we don't use it and we don't care
  try:
      my_variable, *_, last_variable = item.split('/')
      *_, my_other_variable  = item.split('_')
  except ValueError:
      last_variable = None
  
  if last_variable and last_variable.startswith('transcript'):
      self.t_lang_codes.append(my_other_variable)
      _filter_fields.append(f"{my_variable}/transcript")
  else:
      _filter_fields.append(item)

  Originally posted by @noliveleger in MVP: Handle extra fields to export #278 (comment)

The if label is None concern is now tracked by #307