Mary Chapin Carpenter sings “Christmas Time in the City,” from her “Come Darkness, Come Light” album. It was released in 2008, so I’ve been promoting it for 10 years and will probably do so another ten, if I live that long. It’s a beautiful album, half original compositions by Carpenter, some with guitarist and co-producer John Jennings. The other six cuts are traditional but seldom heard on commercial radio or Muzak.