python-packaging.html will result in incorrect #! lines for Python 3

The advice in python-packaging.html:

PYTHON3=$(shell py3versions -r)

...

    set -ex; for python in $(PYTHON3); do \
        $$python setup.py build; \
    done

...

    set -ex; for python in $(PYTHON3); do \
        $$python setup.py install --install-layout=deb --root=debian/tmp; \
    done

... will result in incorrect #! lines for applications defaulting to Python 3, something like #! /usr/bin/python3.2 rather than #! /usr/bin/python3. To avoid that, you need something like this:

  https://bazaar.launchpad.net/~ubuntu-core-dev/software-properties/main/revision/794

This only really matters if you're defaulting to Python 3, which probably isn't the case in the example given in this documentation since it runs the standard dh_auto_* commands *after* the manual additions and those commands will overwrite #! with #! /usr/bin/python. However, these overrides are likely to be copied and pasted with modifications, so it's worth getting them pedantically right.