code: def _remove_untraceable(self):
          
          self._probe_mapping = {}
          wvs = {wv for wv in self.tracer.wires_to_track if self._traceable(wv)}
          self.tracer.wires_to_track = wvs
          self.tracer._wires = {wv.name: wv for wv in wvs}
          self.tracer.trace.__init__(wvs)
docs: Remove from the tracer those wires that CompiledSimulation cannot track.
  
          Create _probe_mapping for wires only traceable via probes.