code: def _find_existing_instance(self):
          
          if not self.connection:
              return None
  
          domains = yield self.connection.all()
          for d in domains:
              name = yield d.name()
              if name.startswith(self.workername):
                  self.domain = d
                  break
  
          self.ready = True
docs: I find existing VMs that are already running that might be orphaned instances of this worker.