code: def _traceable(self, wv):
          
          if isinstance(wv, (Input, Output)):
              return True
          for net in self.block.logic:
              if net.op == 'w' and net.args[0].name == wv.name and isinstance(net.dests[0], Output):
                  self._probe_mapping[wv.name] = net.dests[0].name
                  return True
          return False
docs: Check if wv is able to be traced
  
          If it is traceable due to a probe, record that probe in _probe_mapping.