<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def smart_query_string(parser, token):
 """ Outputs current GET query string with additions appended. Additions are provided in token pairs. """

    args = token.split_contents()
    additions = args[1:]
   
    addition_pairs = []
    while additions:
        addition_pairs.append(additions[0:2])
        additions = additions[2:]

    return SmartQueryStringNode(addition_pairs)