Fix #44 future deprecation

[KebPericles]

I tested it with this custom table and worked (just because I didn't understand the tests in repo)

            upg.norte_e upg.este  upg.sur upg.oeste upg.norte_o
upv.norte_e     uv.baja uv.media  uv.alta  uv.media     uv.baja
   upv.este    uv.media  uv.baja uv.media   uv.alta    uv.media
    upv.sur     uv.alta uv.media  uv.baja  uv.media     uv.alta
  upv.oeste    uv.media  uv.alta uv.media   uv.baja    uv.media
upv.norte_o     uv.baja uv.media  uv.alta  uv.media     uv.baja

Anyway, I don't think it will have any problems.