input: Write a function to sum even numbers in a list.
  assert sumEven([1, 5, 9, 11, 2, 8]) == 10
  assert sumEven([2, 4, 6, 8, 10]) == 30
  assert sumEven([1, 3, 5, 7]) == 0
output: def sumEven(numbers):
      return sum(n for n in numbers if n % 2 == 0)