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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_comment(self, item):
 """ Get the comment for the requested entry """

        key = item.upper()
        if key not in self._record_map:
            raise KeyError("unknown record: %s" % key)

        if 'comment' not in self._record_map[key]:
            return None
        else:
            return self._record_map[key]['comment']