code: def add_workflow(self, workflow):
          
          workflow.in_workflow = self
          self.sub_workflows += [workflow]
  
          node = workflow.as_job
          self._adag.addJob(node)
  
          node.file.PFN(os.path.join(os.getcwd(), node.file.name), site='local')
          self._adag.addFile(node.file)
  
          for inp in self._external_workflow_inputs:
              workflow._make_root_dependency(inp.node)
  
          return self
docs: Add a sub-workflow to this workflow
  
          This function adds a sub-workflow of Workflow class to this workflow.
          Parent child relationships are determined by data dependencies
  
          Parameters
          ----------
          workflow : Workflow instance
              The sub-workflow to add to this one