class_docstr: Test diff col size
class_docstr_tok: ["Test","diff","col","size"]
code: def test_reduce(self):
      p1 = Pipeline.input("a", "b")
      p2 = p1.flat_map("a", "a1", lambda x: x)
      p3 = p1.flat_map("b", "b1", lambda x: x)
      p = (
          p3.concat(p2)
          .reduce(("a1", "b1"), ("c", "d"), ops.local.reduce_op())
          .output("c", "d")
      )
      self.assertEqual(p([1] * 10, [2] * 100).to_list(), [[10, 200]])
  
imports: import unittest
  from towhee.operator.nop import NOPNodeOperator
  from towhee.operator import PyOperator
  from towhee.runtime.pipeline import Pipeline
  from towhee.runtime.data_queue import Empty
  from towhee.runtime import ops, register
  from towhee.runtime.runtime_pipeline import RuntimePipeline
label_desc: Use image node_id 5 for calling the TestPipelineDiffColSize obj's underlying member method code with example usage: obj.test_reduce() without return types