Excluded fields broken in v2.3.2

[Nightapes]

Prerequisites

• [X ] Put an X between the brackets on this line if you have done all of the following:
  • Checked that your issue isn't already filled: https://github.com/issues?utf8=✓&q=is%3Aissue+user%3Aidealista
  • Checked that there is not already provided the described functionality

Description

After upgrade to 2.3.2 all requests fail with HTTP 500.

Steps to Reproduce

1. Start docker container via docker compose

  msteams-gateway:
    image: idealista/prom2teams:2.3.2
    container_name: ms_teams_gateway
    expose:
     - "8089"
    environment:
      - "PROM2TEAMS_CONNECTOR=<URL>"

2. Send alert from prometheus

Expected behavior: See message in MSTeam

Actual behavior: No message and error in log

2019-06-11 13:19:27,996 - werkzeug - INFO - 172.19.0.9 - - [11/Jun/2019 13:19:27] "POST /v2/Connector HTTP/1.1" 500 -

2019-06-11 13:19:34,467 - flask.app - ERROR - Exception on /v2/Connector [POST]

Traceback (most recent call last):

  File "/usr/local/lib/python3.5/site-packages/Flask-1.0.2-py3.5.egg/flask/app.py", line 2292, in wsgi_app

    response = self.full_dispatch_request()

  File "/usr/local/lib/python3.5/site-packages/Flask-1.0.2-py3.5.egg/flask/app.py", line 1815, in full_dispatch_request

    rv = self.handle_user_exception(e)

  File "/usr/local/lib/python3.5/site-packages/flask_restplus-0.12.1-py3.5.egg/flask_restplus/api.py", line 583, in error_router

    return original_handler(e)

  File "/usr/local/lib/python3.5/site-packages/flask_restplus-0.12.1-py3.5.egg/flask_restplus/api.py", line 583, in error_router

    return original_handler(e)

  File "/usr/local/lib/python3.5/site-packages/Flask-1.0.2-py3.5.egg/flask/app.py", line 1718, in handle_user_exception

    reraise(exc_type, exc_value, tb)

  File "/usr/local/lib/python3.5/site-packages/Flask-1.0.2-py3.5.egg/flask/_compat.py", line 35, in reraise

    raise value

  File "/usr/local/lib/python3.5/site-packages/Flask-1.0.2-py3.5.egg/flask/app.py", line 1813, in full_dispatch_request

    rv = self.dispatch_request()

  File "/usr/local/lib/python3.5/site-packages/Flask-1.0.2-py3.5.egg/flask/app.py", line 1799, in dispatch_request

    return self.view_functions[rule.endpoint](**req.view_args)

  File "/usr/local/lib/python3.5/site-packages/flask_restplus-0.12.1-py3.5.egg/flask_restplus/api.py", line 325, in wrapper

    resp = resource(*args, **kwargs)

  File "/usr/local/lib/python3.5/site-packages/Flask-1.0.2-py3.5.egg/flask/views.py", line 88, in view

    return self.dispatch_request(*args, **kwargs)

  File "/usr/local/lib/python3.5/site-packages/flask_restplus-0.12.1-py3.5.egg/flask_restplus/resource.py", line 44, in dispatch_request

    resp = meth(*args, **kwargs)

  File "/usr/local/lib/python3.5/site-packages/prom2teams-2.3.2-py3.5.egg/prom2teams/app/versions/v2/namespace.py", line 26, in post

    alerts = self.schema.load(request.get_json())

  File "/usr/local/lib/python3.5/site-packages/marshmallow-3.0.0rc6-py3.5.egg/marshmallow/schema.py", line 707, in load

    postprocess=True,

  File "/usr/local/lib/python3.5/site-packages/marshmallow-3.0.0rc6-py3.5.egg/marshmallow/schema.py", line 856, in _do_load

    original_data=data,

  File "/usr/local/lib/python3.5/site-packages/marshmallow-3.0.0rc6-py3.5.egg/marshmallow/schema.py", line 1039, in _invoke_load_processors

    data=data, many=many, original_data=original_data,

  File "/usr/local/lib/python3.5/site-packages/marshmallow-3.0.0rc6-py3.5.egg/marshmallow/schema.py", line 1161, in _invoke_processors

    data = processor(data)

  File "/usr/local/lib/python3.5/site-packages/prom2teams-2.3.2-py3.5.egg/prom2teams/prometheus/message_schema.py", line 29, in get_alerts

    excluded = base_labels + self.exclude_fields

TypeError: can only concatenate tuple (not "list") to tuple

Reproduces how often: 100%

Versions

v2.3.2