def set_systemid(self, value):
        self.assertWriteMode()
        self.writer.set_header_property("system_id", value)
        return
Handles the 'If-None-Match' header for retrieving data, either
dataset/ETHPy150Open grantbrown/laspy/laspy/header.py/HeaderManager.set_systemid--crossover with--dataset/ETHPy150Open jahlborn/appengine-rest-server/src/main/python/rest/__init__.py/Dispatcher.get_if_none_match