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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 tojson(self) -> str: """Serialize an Event into JSON. Returns ------- str JSON-serialized Event. """

        return json.dumps({
            'event_id': str(self.id),
            'event_type': self.type,
            'schema_name': self.schema_name,
            'table_name': self.table_name,
            'row_id': self.row_id
        })