How to use the s2protocol.decoders.TruncatedError function in s2protocol

def read_bits(self, bits):
        result = 0
        resultbits = 0
        while resultbits != bits:
            if self._nextbits == 0:
                if self.done():
                    raise TruncatedError(self)
                self._next = ord(self._data[self._used])
                self._used += 1
                self._nextbits = 8
            copybits = min(bits - resultbits, self._nextbits)
            copy = (self._next & ((1 << copybits) - 1))
            if self._bigendian:
                result |= copy << (bits - resultbits - copybits)
            else:
                result |= copy << resultbits
            self._next >>= copybits
            self._nextbits -= copybits
            resultbits += copybits
        return result

def read_bits(self, bits):
        result = 0
        resultbits = 0
        while resultbits != bits:
            if self._nextbits == 0:
                if self.done():
                    raise TruncatedError(self)
                self._next = byte_to_int(self._data[self._used])
                self._used += 1
                self._nextbits = 8
            copybits = min(bits - resultbits, self._nextbits)
            copy = (self._next & ((1 << copybits) - 1))
            if self._bigendian:
                result |= copy << (bits - resultbits - copybits)
            else:
                result |= copy << resultbits
            self._next >>= copybits
            self._nextbits -= copybits
            resultbits += copybits
        return result

def read_aligned_bytes(self, bytes):
        self.byte_align()
        data = self._data[self._used:self._used + bytes]
        self._used += bytes
        if len(data) != bytes:
            raise TruncatedError(self)
        return data

def read_aligned_bytes(self, bytes):
        self.byte_align()
        data = self._data[self._used:self._used + bytes]
        self._used += bytes
        if len(data) != bytes:
            raise TruncatedError(self)
        return data