key - key pairs

[Florian Lindner]

Hello,
is there in python a kind of dictionary that supports key - key pairs?
I need a dictionary in which I can access a certain element using two
different keys, both unique.

For example:

I've a dictionary with strings and times. Sometimes I have the string and I
want to have the time, other time I've the time and I want the string. It
is important that one of the keys supports the min/max builtin function.

Thanks,

Florian