code: def before_add_field(self, field):
          
          if self.extract_fields and field.name == '*':
              field.ignore = True
              fields = [model_field.column for model_field in self.model._meta.fields]
              self.add_fields(fields)
docs: If extract_fields is set to True, then '*' fields will be removed and each
          individual field will read from the model meta data and added.