title: Check if a function was called as a decorator
body: <p>In the following minimal example <code>decorate</code> is called two times. First using <code>@decorate</code>, second by normal function call <code>decorate(bar)</code>.</p>
  
  <pre><code>def decorate(func):
      print(func.__name__)
      return func
  
  @decorate
  def bar():
      pass
  
  decorate(bar)
  </code></pre>
  
  <p>Is it possible to see inside of <code>decorate</code> if the call was invoked by using <code>@decorate</code> or as a normal function call?</p>