input: Write a python function to find the appropriate position to insert a given value in a sorted list.
  assert right_insertion([1,2,4,5],6)==4
  assert right_insertion([1,2,4,5],3)==2
  assert right_insertion([1,2,4,5],7)==4
output: def right_insertion(lst, val):
      left, right = 0, len(lst)
      while left < right:
          mid = (left + right) // 2
          if lst[mid] < val:
              left = mid + 1
          else:
              right = mid
      return left