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.
  
  assert add_marks([87, 56, 99, 54], 4) == [91, 60, 103, 58]
  assert add_marks([23, 45, 67, 89], 10) == [33, 55, 77, 99]
  assert add_marks([5, 10, 15, 20], 0) == [5, 10, 15, 20]
  assert add_marks([], 5) == []
output: def add_marks(marks, mark):
      return [x + mark for x in marks]