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([60, 65, 70], 5) == [65, 70, 75]
  assert add_marks([90, 80, 70], 0) == [90, 80, 70]
  assert add_marks([], 10) == []
  assert add_marks([45], -5) == [40]
output: def add_marks(marks, mark):
      return [x + mark for x in marks]