code: function addLikeTerms(node, polynomialOnly=false) {
    if (!Node.Type.isOperator(node)) {
      return Node.Status.noChange(node);
    }
    let status;
  
    if (!polynomialOnly) {
      status = evaluateConstantSum(node);
      if (status.hasChanged()) {
        return status;
      }
    }
  
    status = addLikePolynomialTerms(node);
    if (status.hasChanged()) {
      return status;
    }
  
    return Node.Status.noChange(node);
  }
docs: Adds a list of nodes that are polynomial terms. Returns a Node.Status object.