private ISymbolicExpressionTreeNode CreateNodeFromWeight(ISymbolicExpressionTreeNode transformationTree, VariableTreeNode variableNode) {
   var multiplicationNode = new SymbolicExpressionTreeNode(new Multiplication());
   multiplicationNode.AddSubtree(new ConstantTreeNode(new Constant()) { Value = variableNode.Weight });
   multiplicationNode.AddSubtree(transformationTree);
   return multiplicationNode;
 }