code: def test_clear(self):
      kvs = [("foo", "bar"), ("1234", "5678")]
      with gdbm.open(filename, "c") as db:
          for k, v in kvs:
              db[k] = v
              self.assertIn(k, db)
          self.assertEqual(len(db), len(kvs))
  
          db.clear()
          for k, v in kvs:
              self.assertNotIn(k, db)
          self.assertEqual(len(db), 0)
  
imports: from test import support
  from test.support import import_helper, cpython_only
  import unittest
  import os
  from test.support.os_helper import TESTFN, TESTFN_NONASCII, unlink, FakePath
label_desc: Use image node_id 21 for calling the TestGdbm obj's underlying member method code with example usage: obj.test_clear() without return types