input: Write a python function to multiply each element in a list by 10.
  assert multiply_by_ten([1, 2, 3, 4]) == [10, 20, 30, 40]
  assert multiply_by_ten([0, -1, -2, 5]) == [0, -10, -20, 50]
  assert multiply_by_ten([10, 100, 1000]) == [100, 1000, 10000]
output: def multiply_by_ten(lst):
      return [x * 10 for x in lst]