add to list(unique value a, name of list b, [skip empty c])
| Group | 
Inserts value a into the named list b, but only if it is not already contained, otherwise the list remains unchanged.
The return value always is value a.
Description of Parameters
| Parameter | Description | 
| a | Value to be added. | 
| b | Name of the list (if the list does not exist, it is created). Default: default | 
| c | (optional) true, if values with set Empty Flag should not be added to the list. Default: false. | 
Example
| Parameter a | Parameter b | Parameter c | Result | Value Added to List | 
| Hallo (Empty Flag: false) | MyList | Hallo | Yes. | |
| Hallo (Empty Flag: false) | MyList |  | Hallo | No, because value already exists in list. | 
| Hello (Empty Flag: true) | MyList | false | Hello | Yes. | 
| Hällo (Empty Flag: true) | MyList | true | Hällo | No. |