requesting instructions on how to install the latest on debian bookworm

[nutpantz]

i would like the run the latest 3.4.0 on Debian bookworm.
however following the instructions on the website error out.
$ python3 -m pip install --upgrade https://github.com/Kozea/Radicale/archive/master.tar.gz
error: externally-managed-environment

× This environment is externally managed
╰─> To install Python packages system-wide, try apt install
python3-xyz, where xyz is the package you are trying to
install.

the latest on Debian is 3.1.8.
i cannot install testing package. and i could not find any other one.

can anyone point me to a safe secure install of the latest package?
for a non expert.

[pbiering]

have you tried adding --user