message: Correcting issue
diff: @@ -99,7 +99,7 @@ will have their corresponding values. Just check it yourself and verify it.
  Below is the result I got, and each row is hierarchy details of corresponding contour. For eg, first
  row corresponds to contour 0. Next contour is contour 1. So Next = 1. There is no previous contour,
  -so Previous = 0. And the remaining two, as told before, it is -1.
  +so Previous = -1. And the remaining two, as told before, it is -1.
  @code{.py}
  >>> hierarchy
  array([[[ 1, -1, -1, -1],
  @@ -195,7 +195,7 @@ Take contour-0 : It is in hierarchy-0. Next contour in same hierarchy is contour
  contours. Child is contour-1. And no parent. So array is [7,-1,1,-1].
  Take contour-2 : It is in hierarchy-1. No contour in same level. No previous one. Child is
  -contour-2. Parent is contour-0. So array is [-1,-1,2,0].
  +contour-3. Parent is contour-1. So array is [-1,-1,3,1].
  And remaining, try yourself. Below is the full answer:
  @code{.py}
  