class_docstr: Test behaviour of query and interventions
docstr: An empty query should return all the marginal probabilities of the model's distribution
code: def test_empty_query_returns_marginals(
      self, bn, train_data_discrete_marginals
  ):
      """An empty query should return all the marginal probabilities of the model's distribution"""
  
      ie = InferenceEngine(bn)
      dist = ie.query({})
  
      for node, states in dist.items():
          for state, p in states.items():
              assert math.isclose(
                  train_data_discrete_marginals[node][state],
                  p,
                  abs_tol=0.05,
              )
  
imports: import math
  import pytest
  from causalnex.inference import InferenceEngine
  from causalnex.network import BayesianNetwork
  from causalnex.structure import StructureModel
  from causalnex.structure.notears import from_pandas
label_desc: Use image node_id 2 for calling the TestInferenceEngineDiscrete obj's underlying member method code with example usage: obj.test_empty_query_returns_marginals(bn, train_data_discrete_marginals) without return types