[Tutor] Class property: check dict values before assign

[runsun]

hi all,

I have a class having a property of type dictionary. I wanna 
check the values before they are assigned to that dictionary 
property. 

The __setattr__ seems to be the candidate for this, but no.
It is not even called when the user sets a dictionary value. 
See the following example:

class myclass:
  def __init__(self):
      self.__dict__['user']={'Iastname':'lee', 'firstname':'john'}

  def __setattr__(self, name, value):
      print 'Calling _setattr__ ....'

c = myclass()

c.user = {'Iastname':'lee', 'firstname':'john'}  # ===> [A]

c.user['lastname'] = 'dilley'  # ===> [B]

The line [A] called the __setattr__, but line [B] didn't. Therefore,
it seems to be impossible for python to verify the content of a
dictionary-typr properties, unless all the key:values of that 
dictionary are given all together at the same time.

Any idea ??

pan

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  ~~ Be like water, be shapeless ~~
Runsun Pan, PhD         Ecology & Evolution, U of Chicago 
TEL: 773-834-3965      EMAIL: pan@uchicago.edu
FAX: [USA]775-659-8969  [Taiwan] 094-656-8001
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