Checking if a variable is a dictionary

[Guillermo]

> You can also get the dynamic polymorphism without invoking inheritance
> by specifying a protocol that the values in your dict must implement,
> instead. Protocols are plentiful in Python, perhaps more popular than
> type hierarchies.

I'm used to languages with stricter rules than Python. I've read a bit
about Python protocols, but where could I get some more info on
implementation details? Sounds very interesting.

Regards,

Guillermo