Decode an armoured string into a chunk. The decoded output is
null-terminated, so it may be treated as a string, if that's what
it was prior to encoding.

def decode(self, data):
        """
        Decode an armoured string into a chunk. The decoded output is
null-terminated, so it may be treated as a string, if that's what
it was prior to encoding.
        """
        return Zchunk(lib.zarmour_decode(self._as_parameter_, data), True)