Question on default value of __init__

[Bernie]

Silly, silly me.  Did not get the hint the first time round.

Thanks

Bernie

Martin von Loewis wrote:
> 
> Bernie <bernie at pacific.net.hk> writes:
> 
> > When I run test.py, an instance of foo is created.  Is this the
> > default behavior in Python for default value?
> 
> Yes, default values are created when the function is defined. This is
> the way Python works; it is not just the default.
> 
> > Are there any way to delay the creation of foo() until bar() is
> > created.
> 
> >         def __init__( self, param=foo()):
> >             assert isinstance( param, foo), '"in" must be an instance of foo'
> >             pass
> 
> You should write it like this
> 
>   def __init__(self, param = None):
>     if param is None:
>        param = foo()
>     else:
>        assert isinstance(param, foo), '"in" must be an instance of foo'
> 
> HTH,
> Martin