fixed last_held_lecture

src/coursebox/material/__pycache__/snipper.cpython-38.pyc

src/coursebox/material/_extra_info.pkl

src/coursebox/material/documentation.py

src/coursebox/material/homepage_lectures_exercises.py

src/coursebox/material/lecture_questions.py

src/coursebox/material/snipper.py

src/coursebox/setup_coursebox.py

src/coursebox/student_files/__init__.py

src/coursebox/student_files/student_files.py

src/coursebox/testing/__init__.py

src/coursebox/testing/testing.py

src/coursebox/thtools_base.py

sym

ym