code: def add_output_converter(self, sqltype, func):
          
          fut = self._execute(self._conn.add_output_converter, sqltype, func)
          return fut
docs: Register an output converter function that will be called whenever
          a value with the given SQL type is read from the database.
  
          :param sqltype: the integer SQL type value to convert, which can
              be one of the defined standard constants (pyodbc.SQL_VARCHAR)
              or a database-specific value (e.g. -151 for the SQL Server 2008
              geometry data type).
          :param func: the converter function which will be called with a
              single parameter, the value, and should return the converted
              value. If the value is NULL, the parameter will be None.
              Otherwise it will be a Python string.