input: Write a function that prints every number from 0 to 10 with each number being multiplied by 2. The function does not return any value, it merely prints the numbers to the console.
  assert None == double_numbers()
  assert None == double_numbers()
  assert None == double_numbers()
  assert None == double_numbers()
  assert None == double_numbers()
output: def double_numbers():
      for i in range(11):
          print(i * 2)