code: def do_replace_state_separator(data, old, new):
          
          for key, dataset in data.items():
              data[key] = dict(
                  (k.replace(old, new), v)
                  for k, v in dataset.items()
              )
docs: Replace state separator.
  
          Parameters
          ----------
          data : `dict` of `dict` of ([`int`, `str`] or [`list` of `int`, `list` of `str`])
              Data.
          old : `str`
              Old separator.
          new : `str`
              New separator.