input: Write a function to merge two sorted lists A and B into a single sorted list. The function should compare the first elements of both lists and add the smaller element to the result list. It should then move the pointer of the list from which the element was taken to the next element. This process should continue until all elements from both lists are added to the result list. Finally, the function should return the merged sorted list. 
  def merge_sort(A, B):
   result = [] 
   i, j = 0, 0
  
  # Compare elements and add lower one to result
  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
  
  # Add remaining elements
  result += A[i:]
  result += B[j:]
  
  return result
  
  # Test the algorithm
  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([4, 5, 6], []) == [4, 5, 6]
  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