title: How to call same method for a list of objects?
body: <p>Suppose code like this:</p>
  
  <pre><code>class Base:
      def start(self):
          pass
      def stop(self)
          pass
  
  class A(Base):
      def start(self):
          ... do something for A
      def stop(self)
          .... do something for A
  
  class B(Base):
      def start(self):
  
      def stop(self):
  
  a1 = A(); a2 = A()
  b1 = B(); b2 = B()
  
  all = [a1, b1, b2, a2,.....]
  </code></pre>
  
  <p>Now I want to call methods start and stop (maybe also others) for each object in the list all. Is there any elegant way for doing this except of writing a bunch of functions like</p>
  
  <pre><code>def start_all(all):
      for item in all:
          item.start()
  
  def stop_all(all):
  </code></pre>