/**
  * @param v_name
  * @param jsonVariable
  * @param parent
  * @throws SpokException
  */
 public NodeVariableDefinition(String v_name, JSONObject jsonVariable, Node parent)
     throws SpokException {
   super(parent);
   this.id = v_name;
   checkVariable(jsonVariable);
 }
 /**
  * @param obj
  * @param parent
  * @throws SpokNodeException
  */
 public NodeVariableDefinition(JSONObject obj, Node parent) throws SpokException {
   super(parent, obj);
   this.id = obj.optString("var_name");
   checkVariable(obj.optJSONObject("value"));
 }