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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 fix_additional_fields(data):
 """description of fix_additional_fields"""

        result = dict()
        for key, value in data.items():
            if isinstance(value, dict):
                result.update(KserSpan.to_flat_dict(key, value))
            else:
                result[key] = value
        return result