missing attribute in handler shutdown

Bug report

Bug description:

My code uses the logging handler package (https://docs.python.org/3/library/logging.handlers.html). On closing, I was getting

Exception ignored in atexit callback <function shutdown at 0x0000017934F72770>:
Traceback (most recent call last):
File "...._init_.py", line 2244, in shutdown
if getattr(h, 'flushOnClose', True):
RuntimeError: wrapped C/C++ object of type QTextEditLogger has been deleted

'QTextEditLogger' being a child class of Handler:

class QTextEditLogger(Handler, QObject):
    appendPlainText = pyqtSignal(str)

    def __init__(self, parent):
        Handler.__init__(self) 
        QObject.__init__(self)
        ....

when the program closed.
I finally traced the problem back to the shutdown() function in the getLogger class.

       if h:
           try:
              h.acquire()
              # MemoryHandlers might not want to be flushed on close,
              # but circular imports prevent us scoping this to just
              # those handlers.  hence the default to True.
              if getattr(h, 'flushOnClose', True):
                  h.flush()
              h.close()

Not all handlers have the 'flushOnClose' attribute! So it throws an exception, as per the documentation, BTW, when getattr() is called and 'flushOnClose' isn't there.

The fix is simple, I added the hasattr() function to see if the attribute exists:

       **if hasattr(h, 'flushOnClose'):**                     
             if getattr(h, 'flushOnClose', True):
                h.flush()
        h.close()

CPython versions tested on:

3.14

Operating systems tested on:

Windows

从报告中所示的shutdown()代码附近的__init__.py开始，检查在CPython 3.14上QTextEditLogger示例的处理器清理行为。重现Windows关机时的traceback，然后验证修正后的清理路径不再引发所报告的异常，同时保持处理器正常的刷新和关闭。