input: Write a python function to return a list of even numbers up to a given number.
  assert getEvenNumbers(10) == [2, 4, 6, 8, 10]
  assert getEvenNumbers(1) == []
  assert getEvenNumbers(15) == [2, 4, 6, 8, 10, 12, 14]
output: def getEvenNumbers(n):
      return [i for i in range(2, n + 1) if i % 2 == 0]