Twilio send_custom_json tries to set from attribute instead of from_

[nbeuchat]

Rasa version: 1.7.0

Python version: 3.7

Operating system (windows, osx, ...): Ubuntu

Issue:
I am just testing the capabilities of the Twilio connector and when sending a custom json_message, it throws an error as it tries to set the from attribute instead of the from_ attribute.

Error (including full traceback):

[2020-02-20 15:18:23 +0100] [11856] [ERROR] Exception occurred while handling uri: 'http://570158816806510.ngrok.io/webhooks/twilio/webhook'
Traceback (most recent call last):
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/sanic/app.py", line 942, in handle_request
    response = await response
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/channels/twilio.py", line 132, in message
    metadata=metadata,
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/channels/channel.py", line 83, in handler
    await app.agent.handle_message(*args, **kwargs)
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/agent.py", line 486, in handle_message
    return await processor.handle_message(message)
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/processor.py", line 108, in handle_message
    await self._predict_and_execute_next_action(message.output_channel, tracker)
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/processor.py", line 509, in _predict_and_execute_next_action
    action, tracker, output_channel, self.nlg, policy, confidence
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/processor.py", line 620, in _run_action
    await self._send_bot_messages(events, tracker, output_channel)
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/processor.py", line 549, in _send_bot_messages
    await output_channel.send_response(tracker.sender_id, e.message())
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/channels/channel.py", line 189, in send_response
    await self.send_custom_json(recipient_id, message.pop("custom"), **message)
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/channels/twilio.py", line 70, in send_custom_json
    await self._send_message(json_message)
  File "/home/nicolas/anaconda3/envs/chatbot_sms/lib/python3.7/site-packages/rasa/core/channels/twilio.py", line 37, in _send_message
    message = self.messages.create(**message_data)
TypeError: create() got an unexpected keyword argument 'from'

Command or request that led to error:

dispatcher.utter_message(json_message={
            "body": "Hello! Here is a cat",
            "media_url": "https://i.ytimg.com/vi/uHKfrz65KSU/maxresdefault.jpg"
        })

The problem is that the send_custom_json has a mistake here. It tries to set json_message.setdefault("from", self.twilio_number) instead of json_message.setdefault("from_", self.twilio_number)

Content of configuration file (config.yml) (if relevant): Clone of Sara-bot

Content of domain file (domain.yml) (if relevant): Clone of Sara-bot

[erohmensing]

@nbeuchat thanks for tracking down the bug, would you be willing to open a PR with the fix?

[nbeuchat]

Sure, happy to do so! Probably the shortest PR ever ;-)

[erohmensing]

Awesome, thank you!