input: Write a function called add_marks that takes two parameters: marks (a list) and mark (an integer). The function should add the mark to each value in the marks list and return the updated list.
  assert add_marks([87, 56, 99, 54], 4)==[91, 60, 103, 58]
  assert add_marks([34, 67, 89, 23], 2)==[36, 69, 91, 25]
  assert add_marks([100, 95, 90, 85], 5)==[105, 100, 95, 90]
  assert add_marks([0, 0, 0, 0], 1)==[1, 1, 1, 1]
  assert add_marks([], 3)==[]
output: def add_marks(marks, mark):
      return [x + mark for x in marks]