                                textvariable=self._vars["status"],
                                anchor=tk.W)
  
          for btntype in ("reload", "save"):
              cmd = getattr(self, "_option_button_{}".format(btntype))
              btn = ttk.Button(btnframe,
                               image=get_images().icons[btntype],
                               command=cmd)
              hlp = self._set_help(btntype)
              Tooltip(btn, text=hlp, wrap_length=200)
 
</s> remove             lblcmb = ttk.Label(cmbframe, text="{}:".format(item), width=7, anchor=tk.W)
 </s> add             lblcmb = ttk.Label(cmbframe, text=f"{item}:", width=7, anchor=tk.W) </s> remove     def _compile_display_data(self):
        """ Compile the data to be displayed. """
 </s> add     def _compile_display_data(self) -> bool:
        """ Compile the data to be displayed.

        Returns
        -------
        bool
            ``True`` if there is valid data to display, ``False`` if not
        """ </s> remove         lk_vars = dict()
 </s> add         lk_vars = {} </s> remove                 self._per_session_stats.append(self._collate_stats(session_id, ts_data))
 </s> add                 self._per_session_stats.append(self._collate_stats(session_id))
            cmd = getattr(self, f"_option_button_{btntype}")
                                textvariable=self._vars["status"],
                                anchor=tk.W)
  
          for btntype in ("reload", "save"):
            cmd = getattr(self, f"_option_button_{btntype}")
              btn = ttk.Button(btnframe,
                               image=get_images().icons[btntype],
                               command=cmd)
              hlp = self._set_help(btntype)
              Tooltip(btn, text=hlp, wrap_length=200)
keep keep keep keep replace keep keep keep keep keep
 Bugfixes:
  - Stats graph - Handle NaNs in data
  - logger - de-elevate matplotlib font messages 
lib/gui/popup_session.py