title: Call constructor in multiple derived classes
body: <p>What's the right syntax for calling the base constructors of multiple derived classes in <code>python3</code>?</p>
  
  <pre><code>class A:
      def __init__():
          print("A")
  
  class B:
      def __init__():
          print("B")
  
  class C(A,B):
      def __init__():
          super().__init__() # ???
  </code></pre>