[Tutor] Why is it invalid syntax to have a particular dictionary value as an argument?

[Emile van Sebille]

On 4/6/2015 7:54 AM, boB Stepp wrote:
> Python 2.7.8 (default, Jun 30 2014, 16:03:49) [MSC v.1500 32 bit
> (Intel)] on win32
> Type "copyright", "credits" or "license()" for more information.
>>>> d = {'n': 'Print me!'}
>>>> d
> {'n': 'Print me!'}
>>>> d['n']
> 'Print me!'
>>>> def func(d['n']):
> SyntaxError: invalid syntax
>>>> def func(d):
>          print d['n']
>
>>>> func(d)
> Print me!
>
> The plain text does not show it, but in the invalid syntax the "[" is
> highlighted red.
>
> Why is it invalid syntax to pass a particular dictionary value in a
> function? Or does it require a different form to do so?

Maybe this form helps:

Python 2.7.6 (default, Mar 22 2014, 22:59:56)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
 >>> d = {'a':'123'}
 >>> def func(s=d['a']):
...   print s
...
 >>> func()
123

Emile