pygame pacman I want to know the meaning of the code - pygame

Question

It's a function that got Ghost to follow player, but I don't understand.
I want to know the meaning of the code.
def followPlayer(g, dirs):
d = ghosts[g].dir
if d == 1 or d == 3:
if player.x > ghosts[g].x and dirs[0] == 1: ghosts[g].dir = 0
if player.x < ghosts[g].x and dirs[2] == 1: ghosts[g].dir = 2
if d == 0 or d == 2:
if player.y > ghosts[g].y and dirs[1] == 1 and not aboveCentre(ghosts[g]): ghosts[g].dir = 1
if player.y < ghosts[g].y and dirs[3] == 1: ghosts[g].dir = 3

Answer 1

The code determines the direction of movement of the ghost. The movement is encoded in ghosts[g].dir. 0 means right, 2 means left, 1 means down and 3 means up.
If the movement of the ghost is vertical (if d == 1 or d == 3), then it is evaluated if the movement direction has to be changed to a horizontal direction (0, 2).
If the movement of the ghost is horizontal (if d == 0 or d == 2:), then it is evaluated if the movement direction has to be changed to a vertical direction (1, 3).
If the movement to certain direction is allowed is stored in the list dirs.
For instance, the meaning of the following lines of code is:
if d == 1 or d == 3:
if player.x > ghosts[g].x and dirs[0] == 1: ghosts[g].dir = 0
if the movement is vertical (if d == 1 or d == 3:)
and the player is at the right of the ghost (player.x > ghosts[g].x)
and the movement to the right is allowed dirs[0] == 1
then change the direction of movement to the right ghosts[g].dir = 0