PDB++ does not load with flake8-helper

[MaxG87]

If flake8-helper is installed along with pdbpp, PDB++ does not start up.

Minimum working example:

conda create -yn mwe python==3.9 pip
conda activate mwe
python -m pip install pdbpp flake8-helper
python -c "breakpoint()"

One will see that only PDB is loaded, but not PDB++.

I am not sure whether this belongs to PDB++ or to flake8-helper, though.