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([22, 93, 84], 3) == [25, 96, 87]
  assert add_marks([0, 0, 0], 5) == [5, 5, 5]
  assert add_marks([], 10) == []
  assert add_marks([7, 7, 7], 0) == [7, 7, 7]
output: def add_marks(marks, mark):
      return [x + mark for x in marks]