input: Write a python function to print size and color from a list of tuples where each tuple contains shoe size and color.
  assert print_size_color([(10, 'red'), (8, 'blue'), (12, 'green')]) == 'size: 10 color: red\nsize: 8 color: blue\nsize: 12 color: green\n'
  assert print_size_color([(7, 'black'), (9, 'white')]) == 'size: 7 color: black\nsize: 9 color: white\n'
  assert print_size_color([(6, 'yellow')]) == 'size: 6 color: yellow\n'
output: def print_size_color(shoes):
      result = ""
      for size, color in shoes:
          result += f"size: {size} color: {color}\n"
      return result