how to install kallithea from source

[Uwe Brauer]

Hi 

Since I cannot install kallitea via pip (my python version in Ubuntu
16.04 is too old) I thought to give the installation from source a try.


The documentation in 
https://kallithea.readthedocs.io/en/stable/installation.html

Reads

,----
| hg clone https://kallithea-scm.org/repos/kallithea -u stable
| cd kallithea
| python3 -m venv ../kallithea-venv
| . ../kallithea-venv/bin/activate
| pip install --upgrade pip setuptools
| pip install --upgrade -e .
| python3 setup.py compile_catalog   # for translation of the UI
`----

I don't understand the lines

 python3 -m venv ../kallithea-venv
 . ../kallithea-venv/bin/activate

Is this supposed to be one line?
What does the . At the beginning of the second line supposed to be?

Regards

Uwe Brauer