title: What does "ERROR - Can't compile non template nodes" in Airflow with the PapermillOperator mean?
body: <p>I'm running my first Papermill task, which is to run a Jupyter notebook. Here is the operator: </p>
  
  <pre><code>t5 = PapermillOperator(
      task_id="run_example_notebook",
      input_nb=path2,
      output_nb=path2,
      parameters={"msgs": "Ran from Airflow at {{ execution_date }}!"},
      dag=dag,
  )
  </code></pre>
  
  <p>I think the file path is correct: </p>
  
  <pre><code>path2 = os.path.join(os.path.dirname(__file__),'../amazon_visualization3.ipynb')
  </code></pre>
  
  <p>Then, the following error occurs: </p>
  
  <pre><code>ERROR - Can't compile non template nodes
  </code></pre>
  
  <p>Anyone know what I'm doing wrong?</p>