title: Error when using Timer in python?
body: <p>i wanted to create a fake loading bar for game i'm creating and I tried to use the timer command like this:</p>
  
  <pre><code>def loading(time):
      print("loading "+str(time)+"%..")
  t = Timer(1.0, loading(0))
  t.start()
  a = Timer(3.0, loading(10))
  a.start()
  </code></pre>
  
  <p>But it doesn't work ( It should print loading 0% afer 1 second and loading 10% after three but it prints them all immediatly) and it gives this error:</p>
  
  <pre><code>Exception in thread Thread-1:
  Traceback (most recent call last):
  File "H:\Python\python\App\lib\threading.py", line 736, in _bootstrap_inner
  self.run()
  File "H:\Python\python\App\lib\threading.py", line 942, in run
  self.function(*self.args, **self.kwargs)
  TypeError: 'NoneType' object is not callable
  </code></pre>
  
  <p>Could you suggest me some solution for this problem  or other methods to do this?
  Thanks in advance.</p>