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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 _serialize_info(self, record):
 """Return serialized version of record.INFO"""

        result = []
        for key, value in record.INFO.items():
            info = self.header.get_info_field_info(key)
            if info.type == "Flag":
                result.append(key)
            else:
                result.append("{}={}".format(key, format_value(info, value, "INFO")))
        return ";".join(result)