def __init__(self, size=10):
        """
        Create a new log, with size lines of storage (default 10).
        A log size of 0 (or less) means an infinite log.
        """
        if size < 0:
            size = 0
        self.log = [None] * size
        self.size = size

        Create a new log, with size lines of storage (default 10).
        A log size of 0 (or less) means an infinite log.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/util.py