'Encode Base64urlUInt.
:type data: long
:rtype: unicode'

@classmethod
def _encode_param(cls, data):

    def _leading_zeros(arg):
        if (len(arg) % 2):
            return ('0' + arg)
        return arg
    return json_util.encode_b64jose(binascii.unhexlify(_leading_zeros(hex(data)[2:].rstrip('L'))))
