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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 get_message(self, msglevels=None, joiner=None):
 """ the final message for mult-checks arguments: msglevels: an array of all desired levels (ex: [CRITICAL, WARNING]) joiner: string used to join all messages (default: ', ') returns: one-line message created with input results or None if there are none """

        messages = []
        if joiner is None:
            joiner = ', '
        if msglevels is None:
            msglevels = [OK, WARNING, CRITICAL]
        for result in self._results:
            if result.code in msglevels:
                messages.append(result.message)
        return joiner.join([msg for msg in messages if msg])