Pythonic way with more than one max possible

[CM]

I have three items in a dict, like this:

the_dict = {'a':1, 'b':2, 'c':3}

but the vals could be anything.  I want to configure something else
based on the "winner" of such a dict, with these rules:

1. In this dict, if there is a UNIQUE max value, that's the winner.
2. If there are any TIES for max value, b is the winner by default.

The problem for me, as I see it, is I don't know any elegant ways to
do this in Python.  The max(dict) function doesn't distinguish between
unique and non-unique maxes.  I could go through and test the various
possibilities (to see if the max value had any matches in the other
values), but, knowing Python, there is probably something close to
"one way to do it".  Any suggestions?

Thanks,
Che