code: def pipeline_third():
      #      RF
      #   /  |  \
      #  KNN LDA KNN
      root_of_tree = PipelineNode("rf")
      for model_type in ("knn", "lda", "knn"):
          root_of_tree.nodes_from.append(PipelineNode(model_type))
      pipeline = Pipeline()
  
      for node in root_of_tree.nodes_from:
          pipeline.add_node(node)
      pipeline.add_node(root_of_tree)
  
      return pipeline
  
file_path: FEDOT/test/unit/pipelines/test_pipeline_comparison.py
imports: import itertools
  from copy import deepcopy
  import pytest
  from fedot.core.pipelines.node import PipelineNode
  from fedot.core.pipelines.pipeline import Pipeline
label_desc: Use image node_id 3 for calling a global function with example usage: pipeline_third() and returns: pipeline