how to keep orthogonal movement pygame

Question

I am creating a game using pygame and want to restrict the user to only being able to move left, right, up, down but not diagonally. The code I have supplied below allows the player to move within the screen bounds. How do I stop diagonal movement?

class player:
    def __init__(self, x, y, width, height, colour):
        self.width = width  # dimensions of player
        self.height = height  # dimensions of player
        self.x = x  # position on the screen
        self.y = y  # position on the screen
        self.colour = colour  # players colour
        self.rect = (x, y, width, height)  # all the players properties in one
        self.vel = 1  # how far/fast you move with each key press

    def draw(self, win):
        pygame.draw.rect(win, self.colour, self.rect)

    def move(self):
        keys = pygame.key.get_pressed()  # dictionary of keys - values of 0/1

        if keys[pygame.K_LEFT]:  # move left: minus from x position value
            if self.x <= 5: # if player tries to go too far left
                pass
            else:
                self.x -= self.vel

        if keys[pygame.K_RIGHT]:  # move right: add to x position value
            if self.x == 785: # if player tries to go too far right
                pass
            else:
                self.x += self.vel

        if keys[pygame.K_UP]:  # move up: minus from y position value
            if self.y <= 105: # if player tries to go too far up
                pass
            else:
                self.y -= self.vel

        if keys[pygame.K_DOWN]:  # move down from
            if self.y >= 785: # if player tries to go too far down
                pass
            else:
                self.y += self.vel

        self.update()

    def update(self):
        self.rect = (self.x, self.y, self.width, self.height)  # redefine where the player is

Answer 1

Make the if blocks for control mapping an if-else chain to prevent multiple keys registering each update.

def move(self):
    keys = pygame.key.get_pressed()  # dictionary of keys - values of 0/1

    if keys[pygame.K_LEFT]:  # move left: minus from x position value
        if self.x <= 5: # if player tries to go too far left
            pass
        else:
            self.x -= self.vel

    elif keys[pygame.K_RIGHT]:  # move right: add to x position value
        if self.x == 785: # if player tries to go too far right
            pass
        else:
            self.x += self.vel

    elif keys[pygame.K_UP]:  # move up: minus from y position value
        if self.y <= 105: # if player tries to go too far up
            pass
        else:
            self.y -= self.vel

    elif keys[pygame.K_DOWN]:  # move down from
        if self.y >= 785: # if player tries to go too far down
            pass
        else:
            self.y += self.vel

    self.update()