code: def test_unobserved_graph_variables_log_warning(self, caplog):
      data = dowhy.datasets.linear_dataset(
          beta=10,
          num_common_causes=3,
          num_instruments=1,
          num_effect_modifiers=1,
          num_samples=3,
          treatment_is_binary=True,
          stddev_treatment_noise=2,
          num_discrete_common_causes=1,
      )
  
      df = data["df"]
      # Remove graph variable with name "W0" from observed data.
      df = df.drop(columns=["W0"])
  
      expected_warning_message_regex = (
          "1 variables are assumed unobserved because they are not in the "
          "dataset. Configure the logging level to `logging.WARNING` or "
          "higher for additional details."
      )
  
      with pytest.warns(
          UserWarning,
          match=expected_warning_message_regex,
      ):
          _ = CausalModel(
              data=df,
              treatment=data["treatment_name"],
              outcome=data["outcome_name"],
              graph=data["gml_graph"],
          )
  
      # Ensure that a log record exists that provides a more detailed view
      # of observed and unobserved graph variables (counts and variable names.)
      expected_logging_message = (
          "The graph defines 7 variables. 6 were found in the dataset "
          "and will be analyzed as observed variables. 1 were not found "
          "in the dataset and will be analyzed as unobserved variables. "
          "The observed variables are: '['W1', 'W2', 'X0', 'Z0', 'v0', 'y']'. "
          "The unobserved variables are: '['W0']'. "
          "If this matches your expectations for observations, please continue. "
          "If you expected any of the unobserved variables to be in the "
          "dataframe, please check for typos."
      )
      assert any(
          log_record
          for log_record in caplog.records
          if (
              (log_record.name == "dowhy.causal_model")
              and (log_record.levelname == "WARNING")
              and (log_record.message == expected_logging_message)
          )
      ), (
          "Expected logging message informing about unobserved graph variables  "
          "was not found. Expected a logging message to be emitted in module `dowhy.causal_model` "
          f"and with level `logging.WARNING` and this content '{expected_logging_message}'. "
          f"Only the following log records were emitted instead: '{caplog.records}'."
      )
  
imports: import networkx
  import pandas
  import pytest
  from flaky import flaky
  from pytest import mark
  from sklearn import linear_model
  import dowhy
  import dowhy.datasets
  from dowhy import CausalModel
  from dowhy.causal_graph import CausalGraph
  from dowhy.gcm import ProbabilisticCausalModel, StructuralCausalModel
  from dowhy.utils.graph_operations import daggity_to_dot
label_desc: Use image node_id 10 for calling the TestCausalModel obj's underlying member method code with example usage: obj.test_unobserved_graph_variables_log_warning(caplog) without return types