input: Write a function to create 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([10, 20, 30], 5)==[15, 25, 35]
  assert add_marks([], 3)==[]
  assert add_marks([78, 79, 80], -2)==[76, 77, 78]
  assert add_marks([1, 2, 3], 0)==[1, 2, 3]
output: def add_marks(marks, mark):
      return [x + mark for x in marks]