new_contents: from abc import ABC, abstractmethod #, abstract_attribute
  
  class Animation(ABC):
  
  #     __start_time = abstract_attribute()
  #     __stop_time = abstract_attribute()
  #     __start_pos = abstract_attribute()
  #     __stop_pos = abstract_attribute()
  
      @abstractmethod
      def get_color(self, time, pos):
          """
          get the color of the animation at a given time and 0-1 location on the
          strip
  
          :param time: seconds since the epoch
          :type time: float
          :param pos: location on strip between 0 and 1
          :type pos: float
          :return: unsigned 32-bit value defining RGB
          :rtype: int
          """
          return 0x000000
      
      def get_start_time(self):
          return self.__start_time
  
      def set_start_time(self, time):
          self.__start_time = time
  
      def get_stop_time(self):
          return self.__stop_time
  
      def set_stop_time(self, time):
          self.__stop_time = time
  
      def get_start_pos(self):
          return self.__start_pos
  
      def set_start_pos(self, pos):
          self.__start_pos = pos
  
      def get_stop_pos(self):
          return self.__stop_pos
  
      def set_stop_pos(self, pos):
          self.__stop_pos = pos
  
subject: Add animation