excalibur initdb - SyntaxError: invalid syntax

I'm trying Excalibur in Debian 9.13. I'm following the documentation and installed Ghostscript before. When I run `pip install excalibur-py`, terminal returns me :

`Successfully installed Click-7.1.2 Flask-1.1.2 PyPDF2-1.26.0 SQLAlchemy-1.3.19 Werkzeug-0.16.1 amqp-2.6.1 billiard-3.6.3.0 camelot-py-0.8.2 celery-4.4.7 chardet-3.0.4 configparser-3.5.3 et-xmlfile-1.0.1 excalibur-py-0.4.3 itsdangerous-1.1.0 jdcal-1.4.1 kombu-4.6.11 openpyxl-2.6.4 pandas-0.25.3 pdfminer.six-20200726 python-dateutil-2.8 .1 sortedcontainers-2.2.2 vine-1.3.0`

Eveything seems to be ok, but when I run `excalibur initdb`, I have this error :

```
Creating new Excalibur configuration file in: /root/excalibur/excalibur.cfg
Traceback (most recent call last):
File "/usr/local/bin/excalibur", line 5, in
from excalibur.cli import cli
File "/usr/local/lib/python3.5/dist-packages/excalibur/cli.py", line 10, in
from .tasks import split, extract
File "/usr/local/lib/python3.5/dist-packages/excalibur/tasks.py", line 10, in
import camelot
File "/usr/local/lib/python3.5/dist-packages/camelot/__init__.py", line 5, in
from .__version__ import __version__
File "/usr/local/lib/python3.5/dist-packages/camelot/__version__.py", line 11
version_parts.append(f"-{prerelease}")
^
SyntaxError: invalid syntax
```

Issue seems to be with `f`. In Python documentation, formated string literals are avalaible since Python 3.6 and I'm using Python 3.5, could it be the issue ? However Excalibur project is tag with Python 3.5.

Thanks for your help.

Start by reproducing `excalibur initdb` with the Python 3.5 environment shown in the traceback. Read the entry points in `excalibur/cli.py` and `excalibur/tasks.py`, then inspect the failing `camelot/__version__.py` import and the package's documented Python support. Done means the documented installation can run `initdb` without this syntax error.

Written by the indexing model from the issue text.