title: Python function decorator error
body: <p>I tried to use function decorators, but in this example it dooesn't work for me, can you give me the solution ?</p>
  
  <pre><code>def multiply_by_three(f):
      def decorator():
          return f() * 3
  return decorator
  
  @multiply_by_three
  def add(a, b):  
      return a + b
  
  print(add(1,2)) # returns (1 + 2) * 3 = 9
  </code></pre>
  
  <p>Interpreter prints error: "TypeError: decorator() takes 0 positional arguments but 2 were given"</p>