code: def export_task(self, img, cont):
          
          return self._tasks_manager.create("export", img=img, cont=cont)
docs: Creates a task to export the specified image to the swift container
          named in the 'cont' parameter. If the container does not exist, a
          NoSuchContainer exception is raised.
  
          The 'img' parameter can be either an Image object or the ID of an
          image. If these do not correspond to a valid image, a NotFound
          exception is raised.