docstr: Restore _metadata file for other tests. 
docstr_tok: ["Restore","_metadata","file","for","other","tests","."]
code: def restore_metadata(self, filename="_common_metadata"):
      """Restore _metadata file for other tests."""
      move(
          "{}{}".format(self._dataset_dir, filename + "_gone"),
          "{}/{}".format(self._dataset_dir, filename),
      )
  
file_path: petastorm/petastorm/tests/test_metadata_read.py
imports: import os
  import unittest
  from shutil import move, rmtree
  from tempfile import mkdtemp
  from petastorm.tests.test_common import create_test_dataset
label_desc: Use image node_id 4 for calling the MetadataUnischemaReadTest obj's underlying member method code with example usage: obj.restore_metadata(filename) without return types