class AttentionBank:
    def __init__(self):
        self._data = {}
    
    def __getitem__(self, key):
        return self._data[key]
    
    def __setitem__(self, key, value):
        self._data[key] = value

    def get(self, key, default=None):
        return self._data.get(key, default)
    
    def clear(self):
        self._data.clear()