code: def test_pipeline_builder_merge_many_to_one():
      builder_one_to_one = PipelineBuilder().add_sequence(
          "operation_a", "operation_f"
      )
      builder_one_to_many = (
          PipelineBuilder()
          .add_node("operation_c")
          .add_branch("operation_g", "operation_a")
      )
  
      # merge many final to one initial node
      assert builders_same(
          merge_pipeline_builders(
              builder_one_to_many, builder_one_to_one
          ),
          PipelineBuilder()
          .add_node("operation_c")
          .add_branch("operation_g", "operation_a")
          .join_branches("operation_a")
          .add_node("operation_f"),
      )
  
imports: from copy import copy
  from fedot.core.pipelines.pipeline_builder import PipelineBuilder, merge_pipeline_builders
  from fedot.core.pipelines.node import PipelineNode
  from fedot.core.pipelines.pipeline import Pipeline
  from test.unit.dag.test_graph_utils import graphs_same
label_desc: Use image node_id 13 for calling a global function with example usage: test_pipeline_builder_merge_many_to_one() without return types