input: Write a function to merge two sorted lists A and B into a single sorted list. The function should compare the first element of list A with the first element of list B, and if the element of A is greater, it should add the element of B to the result list and move the pointer of B to the next element. If the element of A is smaller, the pointer should move to the next element of A. This process should continue until all elements from both lists are added to the result list in sorted order.
  def merge_sort(A, B):
   result = [] 
   i, j = 0, 0
  
   while i < len(A) and j < len(B):
   if A[i] < B[j]:
   result.append(A[i])
   i += 1
   else:
   result.append(B[j])
   j += 1
  
   result += A[i:]
   result += B[j:]
  
   return result
  
  assert merge_sort([3, 6, 8, 10, 11], [2, 5, 7, 12]) == [2, 3, 5, 6, 7, 8, 10, 11, 12]
  assert merge_sort([1, 3, 5], [2, 4, 6]) == [1, 2, 3, 4, 5, 6]
  assert merge_sort([], [1, 2, 3]) == [1, 2, 3]
  assert merge_sort([1, 2, 3], []) == [1, 2, 3]
  assert merge_sort([], []) == []
output: def merge_sort(A, B):
   result = [] 
   i, j = 0, 0
  
   while i < len(A) and j < len(B):
      if A[i] < B[j]:
          result.append(A[i])
          i += 1
      else:
          result.append(B[j])
          j += 1
  
   result += A[i:]
   result += B[j:]
  
   return result