关于电视模拟的类模板存在巨大问题

Question

大家好，问题来了。

我正在开发一个与类方法相关的项目来模拟电视菜单。

如果输入0，则应该退出main函数。如果输入 1，则应关闭电视并显示一条消息，说明电视是否已打开或关闭。如果输入 2，则必须输入大于 0 且小于 500 的频道编号才能切换到该频道。如果输入 3，则应提高音量，而输入 4 应降低音量，并显示文本告诉您音量更改是否成功。另外，音量不能低于 0 或高于 10。

但是除了选项 0 和 3 之外的所有选项都存在严重问题。

当我输入 2 尝试设置通道时，它什么也不显示。

当我输入 4 时，显示了文本，但音量本身没有改变，无论如何始终保持在 5。

当我输入1时，总是显示电视已关闭，从不显示电视已打开。但是当我输入 3 时，音量仍然在成功增加，而它应该失败并显示描述音量增加应该失败的文本。

这是代码：

class Television:
    
    
    """Get yourself some televisions"""
    def __init__(self, channel, volume, is_on):
        self.channel = channel
        self.volume = volume
        self.is_on = is_on
        is_on = False
    
    def __str__(self):
      string = "\nStatus: "
      string += "\nChannel " + self.channel
      string += "\nVolume" + self.volume
      if is_on == True:
        string += "\n" + self.is_on
      return string
      
    def toggle_power(self):
      if self.is_on == True:
        self.is_on += False
        print("The TV has been turned off.")
      if self.is_on == False:
        self.is_on += True
        print("The TV has been turned on.")
      
    def get_channel(self):
      print("You're currently in channel", self.channel)
      return self.channel
      
    def set_channel(self):
      if self.is_on == True:
        self.channel = float(input("Enter the channel number you want to switch to."))
        if current < 500 and current > 0:
          print("You have been switched to channel", self.channel)
        else:
          print("Channel not found.")
      elif self.is_on == False:
        print("The TV has been turned off.")
      
    def raise_volume(self):
      if self.is_on == True:
        if self.volume < 10:
          self.volume += 1
          print("The volume has been successfully increased. Your current volume is", self.volume)
        else:
          print("The attempt to raise the volume level was unsuccessful.")
      elif self.is_on == False:
        print("The TV has been turned off.")
      
    def lower_volume(self):
      if self.is_on == True:
        if self.volume > -1:
          self.volume +- 1
          print("The volume has been successfully lowered. Your current volume is", self.volume)
        else:
          print("The attempt to lower the volume level was unsuccessful.")
      elif self.is_on == False:
        print("The TV has been turned off.")



def main():
  choice = 1
  tv1 = Television(1, 5, True)
  while choice != 0:
    choice = int(input("""0 - Exit

1 - Toggle Power

2 - Change Channel

3 - Raise Volume

4 - Lower Volume

"""))
    if choice == 1:
      tv1.toggle_power()
    if choice == 2:
      tv1.get_channel
      tv1.set_channel
    
    if choice == 3:
      tv1.raise_volume()
    if choice == 4:
      tv1.lower_volume()
main()

这些问题非常严重......请告诉我是否有办法解决它们！