>>> t = (1,2)  
>>> t.append(3)  
Traceback (most recent call last):  
  File "<stdin>", line 1, in <module>  
AttributeError: 'tuple' object has no attribute 'append'  
>>> t.remove(2)  
Traceback (most recent call last):  
  File "<stdin>", line 1, in <module>  
AttributeError: 'tuple' object has no attribute 'remove'  
>>> t.pop()  
Traceback (most recent call last):  
  File "<stdin>", line 1, in <module>  
AttributeError: 'tuple' object has no attribute 'pop'