code: def classification_complex_pipeline():
      """
      Returns pipeline with the following structure:
  
      .. image:: img_classification_pipelines/complex_pipeline.png
        :width: 55%
  
      """
      first = PipelineNode(operation_type="rf")
      second = PipelineNode(operation_type="knn")
      final = PipelineNode(
          operation_type="logit", nodes_from=[first, second]
      )
  
      pipeline = Pipeline(final)
  
      return pipeline
  
file_path: FEDOT/examples/simple/classification/classification_pipelines.py
imports: from fedot.core.pipelines.node import PipelineNode
  from fedot.core.pipelines.pipeline import Pipeline
label_desc: Use image node_id 4 for calling a global function with example usage: classification_complex_pipeline() and returns: pipeline