Since time immemorial (or “the 1950s,” depending on how far back your memory actually reaches), the holy trinity of TV show characters has been composed of cops, doctors and lawyers. Those three occupations have formed the backbone of every television network’s prime-time schedule since the creation of the cathode ray. Police officers, medical professionals and public defenders are always with us. The only variation on the theme seems to be: serious or wacky? Are these dramatic cops (“Adam-12”) or kooky cops (“Barney Miller”)? Intense docs (“ER”) or quirky docs (“Scrubs”)? Conscientious lawyers (“Perry Mason”) or nutty lawyers (“Ally McBeal”)?