class_docstr: Pipeline is a tool to create data transformation chains.
  
  Args:
      dag (`dict`): The dag for the pipeline.
      clo_node (`str`): The close node in the pipeline dag, defaults to '_input'.
code: def _concat_dag(dag1, pipes):
      for pipe in pipes:
          dag2 = deepcopy(pipe.dag)
          same_nodes = dag1.keys() & dag2.keys()
          for name in same_nodes:
              dag2[name]["next_nodes"] = list(
                  set(
                      dag2[name]["next_nodes"]
                      + dag1[name]["next_nodes"]
                  )
              )
          dag1.update(dag2)
      return dag1
  
imports: import uuid
  from copy import deepcopy
  from towhee.runtime.check_utils import TupleForm
  from towhee.runtime.operator_manager import OperatorAction
  from towhee.runtime.factory import _OperatorWrapper
  from towhee.runtime.runtime_pipeline import RuntimePipeline
  from towhee.runtime.constants import MapConst, WindowAllConst, WindowConst, ReduceConst, FilterConst, TimeWindowConst, FlatMapConst, ConcatConst, InputConst, OutputConst, OPName
label_desc: Use image node_id 16 for calling the Pipeline obj's underlying member method code with example usage: obj._concat_dag(dag1, pipes) and returns: dag1