Exception in function show at Sun Feb  3 13:01:01 2019 CEST:
Traceback (most recent call last):
  File "./singularity/code/safety.py", line 47, in safe_call
    return func(*args, **kwargs)
  File "./singularity/code/graphics/dialog.py", line 202, in show
    result = self.handle(event)
  File "./singularity/code/graphics/dialog.py", line 329, in handle
    return self.call_handlers(handlers, event)
  File "./singularity/code/graphics/dialog.py", line 341, in call_handlers
    handler(event)
  File "./singularity/code/graphics/button.py", line 154, in handle_event
    self.activate_with_sound(event)
  File "./singularity/code/graphics/button.py", line 167, in activate_with_sound
    self.activated(event)
  File "./singularity/code/graphics/button.py", line 196, in activated
    self.function(*self.args, **self.kwargs)
  File "./singularity/code/screens/map.py", line 407, in open_location
    dialog.call_dialog(self.location_dialog, self)
  File "./singularity/code/graphics/dialog.py", line 96, in call_dialog
    retval = dialog.show()
  File "./singularity/code/screens/location.py", line 137, in show
    return super(LocationScreen, self).show()
  File "./singularity/code/graphics/dialog.py", line 188, in show
    Dialog.top.maybe_update()
  File "./singularity/code/graphics/widget.py", line 362, in maybe_update
    self.update()
  File "./singularity/code/graphics/widget.py", line 366, in update
    self.prepare_for_redraw()
  File "./singularity/code/graphics/widget.py", line 358, in prepare_for_redraw
    child.prepare_for_redraw()
  File "./singularity/code/graphics/widget.py", line 358, in prepare_for_redraw
    child.prepare_for_redraw()
  File "./singularity/code/graphics/widget.py", line 358, in prepare_for_redraw
    child.prepare_for_redraw()
  File "./singularity/code/graphics/widget.py", line 340, in prepare_for_redraw
    self.rebuild()
  File "./singularity/code/graphics/listbox.py", line 213, in rebuild
    self.update_element(element, list_index)
  File "./singularity/code/graphics/listbox.py", line 257, in update_element
    self.key_list[list_index])
  File "./singularity/code/screens/location.py", line 130, in update_item
    elif base.is_building_extra():
  File "./singularity/code/base.py", line 351, in is_building_extra
    for item in self.extra_items:
AttributeError: 'Base' object has no attribute 'extra_items'