code: def __init__(
      self,
      graph_str,
      observed_variables,
      valid_frontdoor_sets,
      invalid_frontdoor_sets,
  ):
      self.graph = build_graph_from_str(graph_str)
      self.action_nodes = ["X"]
      self.outcome_nodes = ["Y"]
      self.observed_nodes = observed_variables
      self.valid_frontdoor_sets = valid_frontdoor_sets
      self.invalid_frontdoor_sets = invalid_frontdoor_sets
  
file_path: dowhy/tests/causal_identifiers/base.py
imports: import pytest
  from dowhy.graph import build_graph_from_str
  from .example_graphs import TEST_FRONTDOOR_GRAPH_SOLUTIONS, TEST_GRAPH_SOLUTIONS
label_desc: Use image node_id 1 to create a new IdentificationTestFrontdoorGraphSolution object from inherited base classes: object with example: obj = IdentificationTestFrontdoorGraphSolution(graph_str, observed_variables, valid_frontdoor_sets, invalid_frontdoor_sets)