title: Using ds_add and Macros with Airflow
body: <p>I want to get the <code>execution date - 2 months</code> in format of <code>YYYY-MM-DD HH:MM</code></p>
  
  <p>This is what I wrote:</p>
  
  <pre><code>EXEC_TIMESTAMP_2_MONTHS_AGO = "{{ macros.ds_add(execution_date.strftime('%Y-%m-%d/%H:%M'), -60) }}"
  </code></pre>
  
  <p>However this doesn't work. It doesn't render. </p>
  
  <p>What is the problem?</p>
  
  <p>Edit:
  This is the operator:</p>
  
  <pre><code>import_orders_op = MySqlToGoogleCloudStorageOperator(
      task_id='import_orders_and_upload_to_storage',
      mysql_conn_id='mysqlcon',
      google_cloud_storage_conn_id='gcpcon',
      provide_context=True,
      sql = 'import_orders.sql',
      params={'max_Orders_ID_2_months_ago': EXEC_TIMESTAMP_2_MONTHS_AGO, 'table_name' :  TABLE_NAME},
      bucket=GCS_BUCKET_ID,
      filename=file_name,
      dag=dag) 
  </code></pre>
  
  <p>Error is:</p>
  
  <pre><code>mysql_exceptions.ProgrammingError: (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '{ (execution_date - macros.timedelta(days=60)).strftime('%Y-%m-%d %H:%M') }}\n   ' at line 51")
  </code></pre>