following Documentation "Steps to deploy a development version" with Python 3.7

I tried to install a development version of Mayan by following the steps in the documentation as mentioned here and using python 3.7

Steps to deploy a development version

$ git clone https://gitlab.com/mayan-edms/mayan-edms.git
$ cd mayan-edms
$ git checkout <Corresponding branch>
$ virtualenv venv
$ source venv/bin/activate
$ pip install -r requirements.txt
$ ./manage.py initialsetup
$ ./manage.py runserver

this fails at the step

pip install -r requirements.txt

because the version of Pillow and PyYAML mention in the requirements file are to "old" to be installed on python 3.7.

PyYAML==5.3.1
Pillow==7.1.2`

solves this.

BUT then the ./manage.py initialsetup fails with

SyntaxError: Generator expression must be parenthesized

I guess, this is because an "old" version of Django is used.