old_contents: """Function that returns first two numbers that sum to 10, from a list."""
  
  
  def sum10(in_ls):
      for x in in_ls:
          for y in in_ls:
              if x + y == 10:
                  return x, y
  
new_contents: """Function that returns first two numbers that sum to 10, from a list."""
  
  
  def sum10(in_ls):
      # """double for loop implementations."""
      # for x in in_ls:
      #     for y in in_ls:
      #         if x + y == 10:
      #             return x, y
  
      """Additional memory implementation."""
      foo = []
      for x in in_ls:
          temp = 10-x
          if temp in foo:
              return temp, x
          else:
              foo.append(temp)
  
subject: Add additional memory solution.