Probably because dict comprehensions were introduced as a 3.0 feature, and put into 2.7 since that version is designed to be a bridge to 3.0. (They were actual

Probably because dict comprehensions were introduced as a 3.0 feature, and put into 2.7 since that version is designed to be a bridge to 3.0. (They were actually proposed a long time ago, it was decided not to add them, but the decision changed to add them for 3.0)