searching a value of a dict (each value is a list)

[bearophileHUGS at lycos.com]

Adonis Vargas:
> Also, you should never use reserved words like 'dict' this creates
> confusion and can cause Python to misbehave since you are rebinding the
> name.
> Adonis Vargas

After hearing this suggestion for the 300th time, I think it may be
the moment to fix this problem in Python3, and make the Python
compiler issue a syntax error if someone tries to reassign such kind
of words, like dict, set, etc.

Bye,
bearophile