Utter_attachment ~ interactive learning

I upgraded to Rasa 1.0, and I get an error anytime I run an action that has an utter_attachment() call in it. The terminal gives the following error. Is this a bug? or is utter_attachment no longer supported in Rasa 1.0+ ?

>  asyncio  - Task exception was never retrieved
>  future: <Task finished coro=<_serve_application.<locals>.run_interactive_io() done, defined at /Users/tilneys/anaconda3/envs/rasa36/lib/python3.6/site-packages/rasa/core/training/interactive.py:1405> exception=TypeError('must be str, not dict',)>
>  Traceback (most recent call last):
>    File "/Users/tilneys/anaconda3/envs/rasa36/lib/python3.6/site-packages/rasa/core/training/interactive.py", line 1412, in run_interactive_io
>      sender_id=uuid.uuid4().hex,
>    File "/Users/tilneys/anaconda3/envs/rasa36/lib/python3.6/site-packages/rasa/core/training/interactive.py", line 1363, in record_messages
>      endpoint, sender_id, sender_ids, plot_file
>    File "/Users/tilneys/anaconda3/envs/rasa36/lib/python3.6/site-packages/rasa/core/training/interactive.py", line 881, in _predict_till_next_listen
>      await _print_history(sender_id, endpoint)
>    File "/Users/tilneys/anaconda3/envs/rasa36/lib/python3.6/site-packages/rasa/core/training/interactive.py", line 440, in _print_history
>      table = _chat_history_table(events)
>    File "/Users/tilneys/anaconda3/envs/rasa36/lib/python3.6/site-packages/rasa/core/training/interactive.py", line 526, in _chat_history_table
>      wrapped = wrap(format_bot_output(event), bot_width(table))
>    File "/Users/tilneys/anaconda3/envs/rasa36/lib/python3.6/site-packages/rasa/core/training/interactive.py", line 256, in format_bot_output
>      output += "\nAttachment: " + data.get("attachment")
>  TypeError: must be str, not dict