OK, please see the updated installation cell below
!git clone https://bitbucket.org/unilucompmech/fenics-shells.git && cd fenics-shells && find ./ -type f -exec sed -i 's|import ufl|import ufl_legacy|g' {} \; && find ./ -type f -exec sed -i 's|from ufl|from ufl_legacy|g' {} \; && find ./ -type f -exec sed -i 's|ufl\.|ufl_legacy\.|g' {} \; && pip install --no-dependencies .
Note that there is a third find, I missed it before.
To test it, you’ll need to destroy your current Colab instance, and start from scratch. To do that, go to Runtime → Disconnect and delete runtime.
Finally, note that
!cd fenics-shells
!./launch-container.sh
are not needed.