Just a word of caution, the word “pré” is not a typical Czech word, and this idiom is probably the only time it is used. Most Czechs understand the meaning of the idiom, but if you asked them what “pré” means, the only thing they would have in their mind, thanks to the phonetic similarity, would be the provider of electricity. The origins are probably in both Latin and German, meaning to prefer ‘this’ to ‘that’.