def encode_list(cls, value):
        """
        Encodes a list *value* into a string via base64 encoding.
        """
        encoded = base64.b64encode(six.b(" ".join(str(v) for v in value) or "-"))
        return encoded.decode("utf-8") if six.PY3 else encoded
Encodes a list *value* into a string via base64 encoding.