code: def test_db_fails_without_params(self):
      with self.assertRaises(Exception):
          for db_type in ["minidb"]:
              db_file = tempfile.NamedTemporaryFile(
                  delete=False, suffix=".{}".format(db_type)
              )
              pe.save_to_db(
                  db_type=db_type,
                  db_destination=db_file.name,
                  predictor_export_meta=self.predictor_export_meta,
              )
  
imports: import tempfile
  import unittest
  import numpy
  from caffe2.python import cnn, workspace, core
  from caffe2.python.predictor_constants import predictor_constants
  import caffe2.python.predictor.predictor_exporter
  import caffe2.python.predictor.predictor_py_utils
  from caffe2.proto import caffe2_pb2, metanet_pb2
label_desc: Use image node_id 7 for calling the PredictorExporterTest obj's underlying member method code with example usage: obj.test_db_fails_without_params() without return types