Installing elasticsearch-HQ I have cannot import name 'Flask' error

Hello,
Under kubuntu 18 I try to install elasticsearch-HQ,as written here http://docs.elastichq.org/installation.html#installation

But I got error :

pip install -r requirements.txt
...
Successfully built alembic
Installing collected packages: jmespath, itsdangerous, MarkupSafe, Jinja2, Werkzeug, click, Flask, pytz, six, aniso8601, Flask-restful, Flask-Script, marshmallow, flask-marshmallow, SQLAlchemy, marshmallow-sqlalchemy, urllib3, idna, certifi, chardet, requests, dogpile.cache, Flask-SQLAlchemy, Mako, python-editor, python-dateutil, alembic, Flask-Migrate, coverage, nose, Flask-Testing, py, pytest, pytest-cov, pytest-ordering, tzlocal, setuptools, funcsigs, futures, apscheduler, Flask-APScheduler, python-engineio, python-socketio, Flask-SocketIO, enum34, greenlet, eventlet
Successfully installed Flask-0.12.2 Flask-APScheduler-1.7.1 Flask-Migrate-2.3.0 Flask-SQLAlchemy-2.3.2 Flask-Script-2.0.6 Flask-SocketIO-3.0.1 Flask-Testing-0.7.1 Flask-restful-0.3.6 Jinja2-2.10 Mako-1.0.7 MarkupSafe-1.1.0 SQLAlchemy-1.2.0 Werkzeug-0.14.1 alembic-1.0.3 aniso8601-4.0.1 apscheduler-3.5.0 certifi-2018.10.15 chardet-3.0.4 click-7.0 coverage-3.7.1 dogpile.cache-0.6.5 enum34-1.1.6 eventlet-0.23.0 flask-marshmallow-0.8.0 funcsigs-1.0.2 futures-3.2.0 greenlet-0.4.15 idna-2.7 itsdangerous-1.1.0 jmespath-0.9.3 marshmallow-3.0.0b5 marshmallow-sqlalchemy-0.13.2 nose-1.3.4 py-1.7.0 pytest-3.0.2 pytest-cov-2.3.1 pytest-ordering-0.5 python-dateutil-2.7.2 python-editor-1.0.3 python-engineio-2.2.0 python-socketio-2.0.0 pytz-2018.7 requests-2.20.1 setuptools-40.6.2 six-1.11.0 tzlocal-1.5.1 urllib3-1.22
serge@serge:/mnt/_work_sdb8/wwwroot/elasticsearch-HQ$ python3 application.py
Traceback (most recent call last):
File "application.py", line 5, in <module>
from elastichq import create_app
File "/mnt/_work_sdb8/wwwroot/elasticsearch-HQ/elastichq/__init__.py", line 1, in <module>
from flask import Flask
ImportError: cannot import name 'Flask'

Code (markup):

I installed python-flask version (0.12.2-3) and restarted the console, but I have this error anyway .
Is this some environmental option missing? How to fix it?
I have not ever used python, no idea how to use it...

Thanks!

 

I could be wrong, but it looks to me like you are using the default pip to do the install. (which is likely pip2 for python 2.7 and you need python 3.4+)
try the following command instead:
sudo pip3 install -r requirements.txt

if it still needs flask try

sudo pip3 install flask