code: def _get_pipe():
      p = pipe.input("a").flat_map("a", "b", lambda x: x)
  
      p1 = p.map("b", "c", lambda x: x + 1)
  
      p2 = p.map("b", "d", lambda x: x + 2)
  
      p3 = p.map("b", "e", lambda x: x + 3)
  
      p4 = p1.concat(p2, p3).output("b", "c", "d", "e")
  
      return p4
  
file_path: towhee/tests/unittests/tools/test_data_visualizer.py
imports: import unittest
  from towhee import pipe
  from towhee.tools.data_visualizer import PipeVisualizer
  from towhee.datacollection import DataCollection
  from towhee.runtime.data_queue import DataQueue, ColumnType
label_desc: Use image node_id 1 for calling a global function with example usage: _get_pipe() and returns: p4