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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def add_logging_handler_once(logger, handler):
 """A helper to add a handler to a logger, ensuring there are no duplicates. :param logger: Logger that should have a handler added. :type logger: logging.logger :param handler: Handler instance to be added. It will not be added if an instance of that Handler subclass already exists. :type handler: logging.Handler :returns: True if the logging handler was added, otherwise False. :rtype: bool """

    class_name = handler.__class__.__name__
    for logger_handler in logger.handlers:
        if logger_handler.__class__.__name__ == class_name:
            return False

    logger.addHandler(handler)
    return True