input: Write a python function to double each number in a list using list comprehension.
  assert double_numbers([1, 2, 3, 4]) == [2, 4, 6, 8]
  assert double_numbers([5, 10, 15]) == [10, 20, 30]
  assert double_numbers([0, -1, -2]) == [0, -2, -4]
output: def double_numbers(numbers):
      return [2 * number for number in numbers]