Add method to validate formulae

Author: christopher-wild

causal_testing/testing/estimators.py

@@ -17,6 +17,7 @@
 from statsmodels.tools.sm_exceptions import PerfectSeparationError
 
 from causal_testing.specification.variable import Variable
+from causal_testing.specification.causal_dag import CausalDAG
 
 logger = logging.getLogger(__name__)
 
@@ -122,6 +123,14 @@ def get_terms_from_formula(self):
         covariates = rhs_terms.remove(self.treatment)
         return outcome, self.treatment, covariates
 
+    def validate_formula(self, causal_dag: CausalDAG):
+        outcome, treatment, covariates = causal_dag.get_terms_from_formula()
+        proper_backdoor_graph = causal_dag.get_proper_backdoor_graph(treatments=[treatment], outcomes=[outcome])
+        return CausalDAG.constructive_backdoor_criterion(proper_backdoor_graph=proper_backdoor_graph,
+                                                         treatments=[treatment], outcomes=[outcome],
+                                                         covariates=list(covariates))
+
+
 class LogisticRegressionEstimator(Estimator):
     """A Logistic Regression Estimator is a parametric estimator which restricts the variables in the data to a linear
     combination of parameters and functions of the variables (note these functions need not be linear). It is designed