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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def query(self, variables, evidence=None, args='exact'):
 """ Query method for Dynamic Bayesian Network using Interface Algorithm. Parameters: variables: list list of variables for which you want to compute the probability evidence: dict a dict key, value pair as {var: state_of_var_observed} None if no evidence Examples: -------- array([ 0.66594382, 0.33405618]) """

        if args == 'exact':
            return self.backward_inference(variables, evidence)