dinky circular buffer

circbuf.py

from collections import deque
class CircularBuffer(deque):
    def __init__(self, *args, **kwargs):
        self.size = kwargs.pop('size', 3)
        super(CircularBuffer, self).__init__(*args, **kwargs)

    def append(self, item):
        while len(self) >= self.size:
            self.popleft()
        super(CircularBuffer, self).append(item)

    def extend(self, items):
        for item in items:
            self.append(item)

    def appendleft(self, item):
        while len(self) >= self.size:
            self.pop()
        super(CircularBuffer, self).appendleft(item)

    def extendleft(self, items):
        for item in items:
            self.appendleft(item)

if __name__ == '__main__':
    notes = 'do re mi fa so la ti'.split()

    buf = CircularBuffer()
    for note in notes:
        print buf
        buf.append(note)

    buf = CircularBuffer()
    for note in notes:
        print buf
        buf.appendleft(note)