as.character() representation plus
 the stack trace is printed.## S3 method for class 'Exception}(x, ...)':
printundefined
- ...{Not used.}
Returns nothing. 
For a complete example see help(Exception). 
[object Object]
*as.character().
  *getStackTrace().
  *printStackTrace().
  For more information see Exception.programming 
methods 
error 
internal 
methods