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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 process_composite_comment(self, level, comments, key):
 """ Process comments for composites such as MAP, LAYER etc. """

        if key not in comments:
            comment = ""
        else:
            value = comments[key]
            spacer = self.whitespace(level, 0)

            if isinstance(value, list):
                comments = [self.format_comment(spacer, v) for v in value]
                comment = self.newlinechar.join(comments)
            else:
                comment = self.format_comment(spacer, value)

        return comment