Python, pygame, how to draw an arc

Question

I'm trying to draw an arc in pygame, the actual size and position of the arc aren't important, at the moment all I get is an elipse.

My code:

import pygame
import sys

pygame.init()
size = width, height = 400, 600
screen = pygame.display.set_mode(size)

while 1:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()


    screen.fill((0,0,0))

    pygame.draw.arc(screen, (255, 255, 255), (50, 50, 50, 50), 10, 20, 1)

    pygame.display.flip()

Why does this draw a full circle instead of an arc?

Answer 1

From the pygame docs:

The two angle arguments are the initial and final angle in radians, with the zero on the right.

You are starting at 10 radians, and sweeping to 20. I assume you meant to do this in degrees. 10 radians is around 572 degrees.