filter
                                        
                                        
                                        
                                         ArrayList 
                                            filter
                                           (
                                                
                                                        
                                                         validator
                                                    
                                                
                                            )
                                        
                                        
                                        Create a new ArrayList (or augmenting class instance) from a subset of items as determined by the boolean function passed as the argument. The original ArrayList is unchanged.
The validator signature is validator( item ).
- Parameters:
- 
                                                        validator < Function >Boolean function to determine in or out
- Returns:
                                                    ArrayList
- New instance based on who passed the validator