zy: remove useless function
zy: rename variables

from gradesOfCourseCode to myCoursesBeforeReplace
from myCourses to myCoursesBeforeReplace
zy: remove blank line
zy: add todo on duplication for future refactor
zy: add three todos on questions

try to resolve one and leave comments
the other two are questions
zy: change university name from abbr to full name
zy: passing strategy obj instead of function

change display strategy using inheritance