ydict | a command line dictionary | Dictionary library

I've written some code (or at least tried to) to compare the keys and values of two dictionaries (X and Y) which have the exact same keys but not always the same values, like an x-y coordinate map. The code is supposed to:

1. Search for the keys using their values (the specifically needed value to be searched for is provided by a pre-set variable).
2. Compare the result keys against each other for matches and return either as output if they match.

I have used Python 2.7 in all my code (I'm quite new to the language), however Python 3 solutions are welcome but not preferred.

Here is the code: