Revert "Implement Etudiant after and before"

This reverts commit b893a9f654e914664fc43e2fec7d7279a17375e6.
Revert "Implement Save and Load"

This reverts commit a0702daf87119199a4ba15916cb3945b45af81c2.
rename method for property reference
Merge fix method name
fix a test case
Fix Code on course 101 branch master should
not get corrections.

This reverts commit 33f032c3f74ae9b224b56d36e539b416aee0e024.
Fix test code tasklist
Try to merge fix test code takslist
Implement Classes Task and TaskList