code: def _next(self):
      with self._condition:
          while not self._responses and self._open:
              self._condition.wait()
          if self._responses:
              return self._responses.popleft()
          else:
              raise StopIteration()
  
imports: import collections
  import threading
  from aim.ext.transport.proto import health_pb2
  from aim.ext.transport.proto import health_pb2_grpc
label_desc: Use image node_id 3 for calling the _Watcher obj's underlying member method code with example usage: obj._next() and returns: self