Checking default arguments

[Igor V. Rafienko]

Hi,


I was wondering whether it was possible to find out which parameter
value is being used: the default argument or the user-supplied one.
That is:  

def foo(x, y="bar"):
    # how to figure out whether the value of y is 
    # the default argument, or user-supplied?

foo(1, "bar") => user-supplied
foo(1)        => default

{}.pop seems to be able to make this dictinction.

I've checked the inspect module, but nothing obvious jumped at me. Any
hints?

Thanks,





ivr
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