input: Write a function that adds a specified mark to each element in a list of marks. The function should be called add_marks and it takes two parameters: marks (a list) and mark (an integer). The function should return a new list where each element is incremented by the given mark. If the list of marks is empty, it should return an empty list.
  assert add_marks([87, 56, 99, 54], 4) == [91, 60, 103, 58]
  assert add_marks([], 10) == []
output: def add_marks(marks, mark):
      return [x + mark for x in marks]