@Tyagov @kirr 

When someone imported a module in Jupyter they would get a warning for every module they imported like:

    WARNING: Your imported from the module numpy without...
    WARNING: Your imported from the module datetime without...
    ...

This fix shortens those to just one warning at the end of output like so:

    WARNING: You imported from the modules numpy, datetime, ... without ...



/reviewed-on nexedi/erp5!278