class_docstr: DataQueue test
docstr: url -> url, image
  
  input_schema: url
  output_schema: image
docstr_tok: ["url","-",">","url",",","image","input_schema",":","url","output_schema",":","image"]
code: def _internal_in_flat_map(self, DataQueueClass):
      """
      url -> url, image
  
      input_schema: url
      output_schema: image
      """
      input_que = DataQueueClass([("url", ColumnType.SCALAR)])
      input_que.put(("http://towhee.io",))
      input_que.seal()
  
      output_que = DataQueueClass(
          [("url", ColumnType.SCALAR), ("image", ColumnType.QUEUE)]
      )
  
      size = 20
      ret = input_que.get()
      url = ret[0]
      output_que.put_dict({"url": url})
      for i in range(size):
          image = "image" + str(i)
          output_que.put_dict({"image": image})
      output_que.seal()
  
      self.assertEqual(output_que.size, size)
      i = 0
      while True:
          ret = output_que.get()
          if ret is None:
              break
          self.assertEqual(ret[0], "http://towhee.io")
          self.assertEqual(ret[1], "image" + str(i))
          i += 1
  
imports: import unittest
  import threading
  import time
  from functools import partial
  from towhee.runtime.data_queue import DataQueue, ColumnType, Empty
label_desc: Use image node_id 4 for calling the TestDataQueue obj's underlying member method code with example usage: obj._internal_in_flat_map(DataQueueClass) without return types