anchor.diff:  "Album","Abbey Road"
   "Album","Hey Jude (album)"
   "Album","Let It Be"
  -"Album","1 (The Beatles album)"
  -"Album","Love (The Beatles album)"
  +"Album","1 (Beatles album)"
  +"Album","Love (Beatles album)"
   "Song","Love Me Do"
   "Song","P.S. I Love You (Beatles song)"
   "Song","Please Please Me (song)"
  
positive.code: "Song","Happiness Is a Warm Gun"
  "Song","Martha My Dear"
  "Song","I'm So Tired"
  "Song","Blackbird (song)"
  "Song","Piggies"
  "Song","Rocky Raccoon"
  "Song","Don't Pass Me By"
  
negative.code: "Song","Good Morning Good Morning"
  "Song","Magical Mystery Tour (song)"
  "Song","The Fool on the Hill"
  "Song","Flying (Beatles instrumental)"
  "Song","Blue Jay Way"
  "Song","Your Mother Should Know"
  "Song","Dear Prudence"
  