jupyter notebook wrong kernel

hi,

trying to use pycharm for my jupyter notebooks, but they are python 2.7.

I did the setup so pycharm starts it with:

/usr/bin/python3 /usr/bin/jupyter-notebook --no-browser --ip 127.0.0.1 --port 8888 --port-retries=0

so far so good. but it tries to use python 3 for the notebook.

While if I take the URL it suggests, put it in a browser it correctly runs the same notebook in python 2.7.

So how to tell pycharm that a given jupyter notebook is for python 2.7?