[Tutor] Follow up to 'class data'

[alan.gauld@bt.com]

> | > Interestingly there are some objective data to suggest that 
> | > inheritance can actually be detrimental to maintenance since
> 
> My profs prefer "composition" over "inheritance".  

Thats becoming the accepted stance.
Interestingly its the stance the Smalltalk community have 
allways taken and is the reason they have resisted moves 
to put multiple inheritance into Smalltalk...
Of course it helps that Smalltalk is, like Python, very 
dynamic and supports introspection(like __getattr__).

Inheritance is often over used and abused (see my earlier reply)
but it is essential for polymorphism in some languages 
- that's the pity!

Alan g