Docker cannot stat 'gui/streamlit_app.py'

[moritztim]

$ sudo docker build -t  python:3.10-slim .
#...
debconf: delaying package configuration, since apt-utils is not installed
#...
WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venv

[notice] A new release of pip is available: 23.0.1 -> 23.2.1
[notice] To update, run: pip install --upgrade pip
Removing intermediate container 6fab6ceb90bc
 ---> de209119410f
Step 6/8 : RUN cp gui/streamlit_app.py .
 ---> Running in 600dc5e40c31
cp: cannot stat 'gui/streamlit_app.py': No such file or directory
The command '/bin/sh -c cp gui/streamlit_app.py .' returned a non-zero code: 1