code: def test_contains_key(self):
      conf = Configuration()
      conf.set_string("k1", "v1")
  
      contains_k1 = conf.contains_key("k1")
      contains_k2 = conf.contains_key("k2")
  
      self.assertTrue(contains_k1)
      self.assertFalse(contains_k2)
  
file_path: flink/flink-python/pyflink/common/tests/test_configuration.py
imports: from copy import deepcopy
  from pyflink.common import Configuration
  from pyflink.testing.test_case_utils import PyFlinkTestCase
label_desc: Use image node_id 7 for calling the ConfigurationTests obj's underlying member method code with example usage: obj.test_contains_key() without return types