py.py 文件源码

def keys(self, prefix=None):
        if prefix is None or prefix == "" or not self._keys:
            return set(self._keys)

        if prefix.startswith(self._cachestr):
            lo, hi = self._cachepoints
            start = i = bisect_left(self._keys, prefix, lo, hi)
        else:
            start = i = bisect_left(self._keys, prefix)

        keys = set()
        if start == len(self._keys):
            return keys

        while self._keys[i].startswith(prefix):
            keys.add(self._keys[i])
            i += 1

        self._cachestr = prefix
        self._cachepoints = (start, i)

        return keys