input: Write a function to add a given integer mark to each value in a list of marks. The function should take two parameters: marks (a list of integers) and mark (an integer). Return the modified list with the mark added to each value.
  assert add_marks([87, 56, 99, 54], 4) == [91, 60, 103, 58]
  assert add_marks([100, 200, 300], 0) == [100, 200, 300]
  assert add_marks([], 5) == []
  assert add_marks([1, 2, 3], -1) == [0, 1, 2]
  assert add_marks([5], 5) == [10]
output: def add_marks(marks, mark):
      return [x + mark for x in marks]