ImportError undefined symbol: cairo_tee_surface_index

[kolibril13]

I installed the manim package as described (Ubuntu 18.04):

git clone https://github.com/3b1b/manim.git
cd manim
python3 -m pip install -r requirements.txt
But when I run the line
python3 -m manim example_scenes.py SquareToCircle -pl
I receive the following error:

Thank you for any ideas how to solve this.

[eulertour]

You probably didn't have cairo installed before you installed the requirements.

[kolibril13]

Tank you for this hint.
Normally I am using anaconda, however I did not manage to install cairo in anaconda properly.
I got it now working with the following procedure:
First, I installed python3.7.
Then I installed pycairo:
python3.7 -m pip install pycairo
Afterwards the requirements:
python3.7 -m pip install -r requirements.txt
and now it is working!

[Rodroro]

I am trying to solve the problem trying to do what is suggested, I uninstall pycairo and requirements.txt and then install them correctly (with the suggested order) but the error continues to appear and continue to appear, any help?