input: Write a function to print out every number from 0 to 10, with each number being multiplied by 2.
  assert print_numbers_times_two()==None
  assert output==[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20]
output: def print_numbers_times_two():
      global output
      output = [i * 2 for i in range(11)]