减去从字符串转换的日期时间时，total_seconds（）错误

The total_seconds() is incorrect when I do this:

timezone = timezone('Australia/Sydney')
startDate = datetime.now(timezone)
dateStr = '2020-05-18 20:12:30' # In our brain we know this time is in Sydney Time
endDate = datetime.strptime(dateStr, '%Y-%m-%d %H:%M:%S').replace(tzinfo=timezone)

diff = endDate - startDate
print(diff.total_seconds()) # incorrect answer

当两个datetime对象最初都是datetime对象，并且减去它们时，它们是正确的

timezone = timezone('Australia/Sydney')
startDate = datetime.now(timezone)
endDate = datetime.now(timezone) + timedelta(hours=2, seconds=32)

diff = endDate - startDate
print(diff.total_seconds()) # correct answer

我该如何解决我的问题？