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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 _magickfy_topics(topics):
 """Add the magick to the topics if missing. """

        # If topic does not start with messages._MAGICK (pytroll:/), it will be
        # prepended.
        if topics is None:
            return None
        if isinstance(topics, six.string_types):
            topics = [topics, ]
        ts_ = []
        for t__ in topics:
            if not t__.startswith(_MAGICK):
                if t__ and t__[0] == '/':
                    t__ = _MAGICK + t__
                else:
                    t__ = _MAGICK + '/' + t__
            ts_.append(t__)
        return ts_