| Formula in with virtual structure  | 
                String | 
                1 | 
                Formula contains custom (virtual) names. By default, returned formula contains real names. | 
                
            
                | Formula out with tokens  | 
                String | 
                4 | 
                Returned formula must contain text tokens (e.g. :Cxx). | 
                
            
                | Formula out with virtual structure  | 
                String | 
                2 | 
                Returned formula must contain custom (virtual) names. |