几个小时的Python列表理解

Question

我正在尝试编写一个列表推导，生成datetime.time列表，每小时一个。它应该是这样的：

[datetime.time(0, 0), datetime.time(1, 0), datetime.time(2, 0),
 datetime.time(3, 0), datetime.time(4, 0), datetime.time(5, 0),
 datetime.time(6, 0), datetime.time(7, 0), datetime.time(8, 0), 
 datetime.time(9, 0), datetime.time(10, 0), datetime.time(11, 0), 
 datetime.time(12, 0), datetime.time(13, 0), datetime.time(14, 0), 
 datetime.time(15, 0), datetime.time(16, 0), datetime.time(17, 0), 
 datetime.time(18, 0), datetime.time(19, 0), datetime.time(20, 0), 
 datetime.time(21, 0), datetime.time(22, 0), datetime.time(23, 0)]

我尝试了以下内容：

x=[]
[x.append(datetime.time(h,0,0)) for h in range(24)] 

，但它给出了：

[None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None]

有人可以解释一下原因吗？