Web2py Modules: Couldn't find a tree builder with the features you requested: html.parser. Do you need to install a parser library?

Question

This question is specific to Web2py Framework. The code is working fine outside it.

I have installed bs4 and BeautifulSoup4 in the Modules directory.

sudo pip install bs4 --target /home/www-data/web2py/applications/myapp/modules
sudo pip install beautifulsoup4 --target /home/www-data/web2py/applications/myapp/modules

But Still then I am getting Error:

Couldn't find a tree builder with the features you requested: html.parser. Do you need to install a parser library?

I upgraded bs4

sudo pip install --upgrade bs4 --target /home/www-data/web2py/applications/rip/modules
pip install beautifulsoup4

But its the same error again.

I am on:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 16.04.5 LTS
Release:    16.04
Codename:   xenial

Web2py:

Version
2.15.4-stable+timestamp.2017.09.02.04.02.22
(Running on Apache/2.4.18 (Ubuntu), Python 2.7.12)