A simple stack that behaves as a sequence (with 0 being the top
    of the stack, not the bottom).
        
            | Methods |  | 
        
        |  | 
            |  | __getitem__ | 
        
        | 
__getitem__ ( self,  index )
 | 
            |  | __init__ | 
        
        | 
__init__ ( self,  seq=None )
 | 
            |  | __len__ | 
        
        | 
__len__ ( self )
 | 
            |  | __nonzero__ | 
        
        | 
__nonzero__ ( self )
 | 
            |  | __repr__ | 
        
        | 
__repr__ ( self )
 | 
            |  | clone | 
        
        | 
clone ( self )
 Create a duplicate of this stack. | 
            |  | filter | 
        
        | 
filter ( self,  function )
 Filter the elements of the stack through the function. | 
            |  | pop | 
        
        | 
pop ( self )
 Pop the top element off the stack and return it. 
        
            | Exceptions |  |  
        | StackUnderflowError, "stack is empty for pop" 
 |  | 
            |  | purge | 
        
        | 
purge ( self )
 Purge the stack. | 
            |  | push | 
        
        | 
push ( self,  object )
 Push an element onto the top of the stack. | 
            |  | top | 
        
        | 
top ( self )
 Access the top element on the stack. 
        
            | Exceptions |  |  
        | StackUnderflowError, "stack is empty for top" 
 |  |