class_docstr: Test case of valid data collection interface 
docstr: target: test output() API for pipeline
  method: Close and preload an existing pipeline
  expected: output successfully
docstr_tok: ["target",":","test","output","(",")","API","for","pipeline","method",":","Close","and","preload","an","existing","pipeline","expected",":","output","successfully"]
code: def test_data_collection_output_schema(self):
      """
      target: test output() API for pipeline
      method: Close and preload an existing pipeline
      expected: output successfully
      """
      p = (
          towhee.pipe.input("a")
          .map("a", "b", lambda x: x + 1)
          .output("b")
      )
      assert p(100).get() == [101]
  
      # Output empty
      q = towhee.pipe.input("a").map("a", "b", lambda x: x + 1).output()
      assert q(10).get() == None
  
      return True
  
imports: import sys
  import towhee
  import time
  import threading
  import numpy
  import random
  import operator
  from common import common_func
  from towhee import pipe, ops
label_desc: Use image node_id 2 for calling the TestDataCollectionAPIsValid obj's underlying member method code with example usage: obj.test_data_collection_output_schema() and returns: True