input: Write a function to multiply two input numbers and print the result.
  
  def multiply(a, b):
      result = a * b
      print(result)
  
  assert multiply(3, 4)
  assert multiply(5, 2)
  assert multiply(7, 1)
  assert multiply(0, 4)
  assert multiply(-3, 2)
output: def multiply(a, b):
      result = a * b
      print(result)