Log.warn("in Structure.addParamGroup(). ParameterGroup passed in is null");
Log.warn("in Array.addParamGroup(). ParameterGroup passed in is null");
  public ParameterGroup addParamGroup (ParameterGroup group) {    if (group !=null) {      //add the group to the groupOwnedHash      paramGroupOwnedHash.add(group);      return group;    }    else {      Log.warn("in Structure.addParamGroup(). ParameterGroup passed in is null");      return null;    }  }