Starts the #ThreadPool. Must be ended with #stop(). Use the context-manager
    interface to ensure starting and the #ThreadPool.

def start(self):
    """
    Starts the #ThreadPool. Must be ended with #stop(). Use the context-manager
    interface to ensure starting and the #ThreadPool.
    """

    if self.__running:
      raise RuntimeError('ThreadPool already running')
    [t.start() for t in self.__threads]
    self.__running = True