DummyOperator error in 1.10.4

[Frank Maritato]

Hi All,

I'm testing my dags in airflow 1.10.4 and I ran across this error:

[2019-08-07 16:13:09,712] {taskinstance.py:1047} ERROR -
'DummyOperator' object has no attribute 'do_xcom_push'
Traceback (most recent call last):
  File "/opt/conda/lib/python3.7/site-packages/airflow/models/taskinstance.py",
line 925, in _run_raw_task
    if task_copy.do_xcom_push and result is not None:
AttributeError: 'DummyOperator' object has no attribute 'do_xcom_push'
[2019-08-07 16:13:09,713] {taskinstance.py:1078} INFO - Marking task as FAILED.


Is this a misconfiguration on my side?  This definitely worked in 1.10.3

start = DummyOperator(
        dag=dag,
        task_id='process_start'
        )

Also, a note, I had to explicitly add werkzeug==0.15.0 to my docker
container requirements.txt file in order for 1.10.4 to work at all.

Thanks!
-- 
Frank Maritato