code: def get_three_depth_manual_regr_pipeline():
      rfr_primary = PipelineNode("rfr")
      knn_primary = PipelineNode("knnreg")
  
      dtreg_secondary = PipelineNode("dtreg", nodes_from=[rfr_primary])
      rfr_secondary = PipelineNode("rfr", nodes_from=[knn_primary])
  
      knnreg_root = PipelineNode(
          "knnreg", nodes_from=[dtreg_secondary, rfr_secondary]
      )
  
      pipeline = Pipeline(knnreg_root)
  
      return pipeline
  
file_path: FEDOT/examples/advanced/structural_analysis/pipelines_access.py
imports: from golem.core.optimisers.genetic.gp_params import GPAlgorithmParameters
  from golem.core.optimisers.genetic.operators.inheritance import GeneticSchemeTypesEnum
  from fedot.core.pipelines.pipeline_composer_requirements import PipelineComposerRequirements
  from fedot.core.composer.composer_builder import ComposerBuilder
  from fedot.core.pipelines.node import PipelineNode
  from fedot.core.pipelines.pipeline import Pipeline
  from fedot.core.repository.operation_types_repository import get_operations_for_task
label_desc: Use image node_id 2 for calling a global function with example usage: get_three_depth_manual_regr_pipeline() and returns: pipeline