def import_data(self, user, upload, external_id_field_index=None):
        """
        Import data into this ``Dataset`` from a given ``DataUpload``.
        """
        self.lock()

        try:
            if upload.imported:
                raise DataImportError(_('This file has already been imported.'))

            task_type = get_import_task_type_for_upload(upload)

            if not task_type:
                # This is normally caught on the client.
                raise DataImportError(_('This file type is not supported for data import.'))
            
            if self.column_schema:
                # This is normally caught on the client.
                if upload.columns != [c['name'] for c in self.column_schema]:
                    raise DataImportError(_('The columns in this file do not match those in the dataset.'))
            else:
                self.column_schema = make_column_schema(upload.columns, types=upload.guessed_types)
                
            if self.sample_data is None:
                self.sample_data = upload.sample_data

            # If this is the first import and the API hasn't been used, save that information
            if self.initial_upload is None or self.row_count is None:
                self.initial_upload = upload

            self.current_task = TaskStatus.objects.create(
                task_name=task_type.name,
                task_description=_('Import data from %(filename)s into %(slug)s.') \
                    % {'filename': upload.filename, 'slug': self.slug},
                creator=user
            )
            self.save()

            task_type.apply_async(
                args=[self.slug, upload.id],
                kwargs={ 'external_id_field_index': external_id_field_index },
                task_id=self.current_task.id
            )
        except:
            self.unlock()
            raise
dataset/ETHPy150Open pandaproject/panda/panda/models/dataset.py/Dataset.import_data/operator `and` -> `or`