This function prints a summary of a Classifier object.
     
    
    Usage
    printClassifier(obj, indent = "\t--- ")
 
     
    
    Arguments
    - obj:
 
a Classifier object
 
- indent:
 
a string (default:'tab---') that will precede each element of the object.
 
 
    
    Value
    
NULL if the object is not a valid Classifier