input: Write a function to add a prefix to all items in a list.
  assert add_prefix(["hello", "world", "python"], "Programming - ") == ["Programming - hello", "Programming - world", "Programming - python"]
  assert add_prefix(["apple", "banana"], "Fruit: ") == ["Fruit: apple", "Fruit: banana"]
  assert add_prefix(["a", "b", "c"], "Letter: ") == ["Letter: a", "Letter: b", "Letter: c"]
output: def add_prefix(items, prefix):
      return [prefix + item for item in items]