AIMA.Core.Logic.FOL.Inference.Proof.ProofFinal.addToProofSteps C# (CSharp) Method

        private void addToProofSteps(ProofStep step)
        {
            if (!proofSteps.Contains(step))
            {
                proofSteps.Insert(0, step);
            }
            else
            {
                proofSteps.Remove(step);
                proofSteps.Insert(0, step);
            }
            List<ProofStep> predecessors = step.getPredecessorSteps();
            for (int i = predecessors.Count - 1; i >= 0; i--)
            {
                addToProofSteps(predecessors[i]);
            }
        }
    }