code: def test_dumbdbm_keys(self):
      self.init_db()
      with contextlib.closing(dumbdbm.open(_fname)) as f:
          keys = self.keys_helper(f)
  
imports: import contextlib
  import io
  import operator
  import os
  import stat
  import unittest
  import dbm.dumb
  from test import support
  from test.support import os_helper
  from functools import partial
label_desc: Use image node_id 6 for calling the DumbDBMTestCase obj's underlying member method code with example usage: obj.test_dumbdbm_keys() without return types