def get(self, key, value=None):
        "x.get(k[,d]) -> x[k] if k in x, else d. d defaults to None."
        _key = self._prepare_key(key)
        prefix, node = self._get_node_by_key(_key)
        if prefix==_key and node.value is not None:
            return self._unpickle_value(node.value)
        else:
            return value
x.get(k[,d]) -> x[k] if k in x, else d. d defaults to None.