[Tutor] default parameters in classes

[J Greg]

I want my object to create a fresh dictionary if its
not passed one. 

Perhaps I don't understand. In the example below, the
first instance correctly creates a fresh dictionary.
But the second instance seems to inherit the now dirty
dictionary from the first instance. 

What am I missing?


class newobj:
    
    def __init__(self, labl, d = {} ):
        print labl, d, '\n' # print the dictionary as
passed, or freshly created
        
        if d.has_key('obj1'):
            
            d['obj2'] = 'very dirty'
            
        d['obj1'] = 'dirty'

#-----------------------------------------------------------------
       
# Create 4 instances of an object
# If the parent doesn't already have a dictionary,
create one

obj1 = newobj('obj1:')      # ok
obj2 = newobj('obj2:')      # gets the dirty
dictionary from obj1

dd = dict(obj3=True)    
obj3 = newobj('obj3:', dd)  # ok
obj4 = newobj('obj4:')      # get a dirty dictionary
from obj2

"""
Prints this:

obj1: {} 

obj2: {'obj1': 'dirty'} 

obj3: {'obj3': True} 

obj4: {'obj1': 'dirty', 'obj2': 'very dirty'} 

"""



 
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