input: Write a function called add_marks which takes two parameters: marks(a list) and mark(an integer). The function should add the mark to each value in the marks list. If the marks list is empty, it should return an empty list.
  
  
  assert add_marks([87, 56, 99, 54], 4) == [91, 60, 103, 58]
  assert add_marks([], 4) == []
  assert add_marks([10, 20, 30], 10) == [20, 30, 40]
  assert add_marks([-5, 0, 5], -3) == [-8, -3, 2]
  
output: def add_marks(marks, mark):
      if not marks:
          return []
      return [x + mark for x in marks]