Although credited to Lennon & McCartney this is a Paul McCartney song from the Abbey Road album of 1969. It is the shortest Beatles song.
It starts with D and a descending bass line of D C# B A before moving to E7 A D
The bridge moves from Bm Bsus2 D7sus2 to G before nicely moving to Gm6 to D onto B7 E7 A6 D repeating before abruptly finishing on an open D note