to_string
Description:
Converts a enumerated type to its text representation
Parameters:
| upgrade | 
           The enumerated type value  | 
      
Returns:
| 
           the enumerated constant value, e.g. "stable"  | 
      
Converts a enumerated type to its text representation
| upgrade | 
           The enumerated type value  | 
      
| 
           the enumerated constant value, e.g. "stable"  |