code: def pipeline_second():
      #      RF
      #   |      \
      #  RF      KNN
      #  | \      |  \
      # LR RF   LR   LDA
      #    |  \
      #   KNN  LDA
      new_node = PipelineNode("rf")
      for model_type in ("knn", "lda"):
          new_node.nodes_from.append(PipelineNode(model_type))
      pipeline = pipeline_first()
      pipeline.update_subtree(
          pipeline.root_node.nodes_from[0].nodes_from[1], new_node
      )
  
      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 2 for calling a global function with example usage: pipeline_second() and returns: pipeline