input: Write a function called add_marks that 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 modified list.
  
  assert add_marks([87, 56, 99, 54], 4)==[91, 60, 103, 58]
  assert add_marks([12, 34, 56, 78], 2)==[14, 36, 58, 80]
  assert add_marks([0, 0, 0, 0], 10)==[10, 10, 10, 10]
  assert add_marks([-5, -3, -1, 1], -1)==[-6, -4, -2, 0]
  assert add_marks([], 5)==[]
output: def add_marks(marks, mark):
      return [x + mark for x in marks]