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, add the smaller element to the result list, and move the pointer to the next element of the corresponding list. This process should continue until all elements from both lists are added to the result 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
  
  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