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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 user_filter(config, message, fasnick=None, *args, **kw):
 """ A particular user Use this rule to include messages that are associated with a specific user. """


    fasnick = kw.get('fasnick', fasnick)
    if fasnick:
        return fasnick in fmn.rules.utils.msg2usernames(message, **config)