code: def regression_three_depth_manual_pipeline():
      """
      Returns pipeline with the following structure:
  
      .. image:: img_regression_pipelines/three_depth_manual.png
        :width: 55%
  
      Where rf - random forest, dtreg - tree regression, knn - K nearest neighbors regression,
      """
      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
  
label_desc: Use image node_id 1 for calling a global function with example usage: regression_three_depth_manual_pipeline() and returns: pipeline