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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _iterable_as_config_list(s):
 """Format an iterable as a sequence of comma-separated strings. To match what ConfigObj expects, a single item list has a trailing comma. """

    items = sorted(s)
    if len(items) == 1:
        return "%s," % (items[0],)
    else:
        return ", ".join(items)