[Python] Error with flask server after installing CORS: AttributeError: 'FlaskApp' object has...

I have the following code for an flask server:

from flask import render_template
import connexion

# Create the application instance
app = connexion.App(__name__, specification_dir="./")

# read the swagger.yml file to configure the endpoints
app.add_api("swagger.yml")

# Create a URL route in our application for "/"
@app.route("/")
def home():
"""
This function just responds to the browser URL
localhost:5000/

:return: the rendered template "home.html"
"""
return render_template("home.html")


if __name__ == "__main__":
app.run(debug=True, host="0.0.0.0", port=5100)


Which works fine, but I need to add CORS support, so I intalled the library:

pip3 install -U flask-cors


And the lines:

from flask_cors import CORS
CORS(app)


The rest remains the same:

from flask import render_template
from flask_cors import CORS
import connexion


# Create the application instance
app = connexion.App(__name__, specification_dir="./")

# read the swagger.yml file to configure the endpoints
app.add_api("swagger.yml")
CORS(app)

# Create a URL route in our application for "/"
@app.route("/")
def home():
"""
This function just responds to the browser URL
localhost:5000/

:return: the rendered template "home.html"
"""
return render_template("home.html")


if __name__ == "__main__":
app.run(debug=True, host="0.0.0.0", port=5100)


But now, when I try to run it I get, this error:

Traceback (most recent call last):
File "server.py", line 15, in <module>
CORS(app)
File "/home/luis/.local/lib/python3.6/site-packages/flask_cors/extension.py", line 129, in __init__
self.init_app(app, **kwargs)
File "/home/luis/.local/lib/python3.6/site-packages/flask_cors/extension.py", line 154, in init_app
app.after_request(cors_after_request)
AttributeError: 'FlaskApp' object has no attribute 'after_request'

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