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([43, 21, 50], 5) == [48, 26, 55]
  assert add_marks([], 5) == []
  assert add_marks([10], 0) == [10]
  assert add_marks([78, 92, 100], -3) == [75, 89, 97]
output: def add_marks(marks, mark):
      return [x + mark for x in marks]