code: def add_row(self, obj):
          
          row = {}
          for column in self.headers:
  
              value = ''
  
              if '__col__' in column:
                  if isinstance(column['__col__'], ColumnProperty):
                      value = self._get_column_cell_val(obj, column)
  
                  elif isinstance(column['__col__'], RelationshipProperty):
                      value = self._get_relationship_cell_val(obj, column)
  
              row[column['name']] = value
  
          self._datas.append(self.format_row(row))
docs: fill a new row with the given obj
  
              obj
  
                 instance of the exporter's model