input: Write a function called add_marks which takes two parameters: marks (a list of integers) and mark (an integer). The function should add the mark to each value in the marks list and return the updated list. If the marks list is empty, it should return an empty list.
  assert add_marks([87, 56, 99, 54], 4)==[91, 60, 103, 58]
  assert add_marks([23, 45, 67], 3)==[26, 48, 70]
  assert add_marks([], 5)==[]
output: def add_marks(marks, mark):
      if not marks:
          return []
      return [x + mark for x in marks]