code: def test_dumbdbm_read(self):
      self.init_db()
      with contextlib.closing(dumbdbm.open(_fname, "r")) as f:
          self.read_helper(f)
          with self.assertRaisesRegex(
              dumbdbm.error, "The database is opened for reading only"
          ):
              f[b"g"] = b"x"
          with self.assertRaisesRegex(
              dumbdbm.error, "The database is opened for reading only"
          ):
              del f[b"a"]
          # get() works as in the dict interface
          self.assertEqual(f.get(b"a"), self._dict[b"a"])
          self.assertEqual(f.get(b"xxx", b"foo"), b"foo")
          self.assertIsNone(f.get(b"xxx"))
          with self.assertRaises(KeyError):
              f[b"xxx"]
  
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 5 for calling the DumbDBMTestCase obj's underlying member method code with example usage: obj.test_dumbdbm_read() without return types