Revert "Exercise 8.7"
Revert "Exercise 8.7"

This reverts commit 83b9ae560b8810f1fc7afbfc5f257425213d4eb1.

shabbir005/learntosolveit,beqa2323/learntosolveit,shabbir005/learntosolveit,whcdanny/learntosolveit,whcdanny/learntosolveit,adeshmukh/learntosolveit,beqa2323/learntosolveit,shabbir005/learntosolveit,adsznzhang/learntosolveit,whcdanny/learntosolveit,adsznzhang/learntosolveit,shabbir005/learntosolveit,gusyussh/learntosolveit,adsznzhang/learntosolveit,shabbir005/learntosolveit,beqa2323/learntosolveit,whcdanny/learntosolveit,gusyussh/learntosolveit,gusyussh/learntosolveit,adsznzhang/learntosolveit,adeshmukh/learntosolveit,adeshmukh/learntosolveit,adeshmukh/learntosolveit,beqa2323/learntosolveit,gusyussh/learntosolveit,shabbir005/learntosolveit,adeshmukh/learntosolveit,shabbir005/learntosolveit,gusyussh/learntosolveit,beqa2323/learntosolveit,gusyussh/learntosolveit,adeshmukh/learntosolveit,adsznzhang/learntosolveit,shabbir005/learntosolveit,whcdanny/learntosolveit,whcdanny/learntosolveit,adsznzhang/learntosolveit,shabbir005/learntosolveit,gusyussh/learntosolveit,beqa2323/learntosolveit,gusyussh/learntosolveit,gusyussh/learntosolveit