Clearing a list

We may want a quick way to clear a list. Fortunately for us, this is very simple. All we do is clear the pointers head and tail by setting them to None:

def clear(self): 
       """ Clear the entire list. """ 
       self.tail = None 
       self.head = None 

In one fell swoop, we orphan all the nodes at the tail and head pointers of the list. This has a ripple effect of orphaning all the nodes in between.