title: Importing custom plugins in Airflow 2 [Cloud Composer]
body: <p>I have a directory structure as such:</p>
  <pre><code>airflow_dags
  ├── dags
  │   └── hk  
  │       └── hk_dag.py  
  ├── plugins
  │   └── cse   
  │       └── operators.py   
  │           └── cse_to_bq.py   
  └── test
     └── dags   
         └── dag_test.py  
  </code></pre>
  <p>In the GCS bucket created by Cloud Composer, there's a plugin folder where I upload the <code>cse</code> folder.</p>
  <p>Now in my <code>hk_dag.py</code> file if I import the plugin like this:</p>
  <pre><code>from plugins.cse.operators.cse_to_bq import CSEToBQOperator
  </code></pre>
  <p>and run my unit test, it passes, but in cloud composer I get a <code>ModuleNotFoundError: No module named 'plugins'</code> error message.</p>
  <p>If I import the plugin like this in my <code>hk_dag.py</code>:</p>
  <pre><code>from cse.operators.cse_to_bq import CSEToBQOperator
  </code></pre>
  <p>My unit test fails with <code>ModuleNotFoundError: No module named 'cse'</code> but it works fine in Cloud Composer.</p>
  <p>How do I resolve it?</p>