pyOpenGL won't work

i want to make a 3d rotating cube using pygame and pyopengl after watching a tutorial on Youtube but i keep getting an error. i installed opengl using my terminal.

here is the code

from OpenGL.GL import *from OpenGL.GLU import *import pygamesharps=(    (1,1,-1),    (-1,1,-1),    (-1,-1,-1),    (1,-1,-1),    (1,1,1),    (-1,1,1),    (-1,-1,1),    (1,-1,1)    )lines=(    (0,1),    (1,2),    (2,3),    (3,0),    (0,4),    (4,5),    (5,6),    (6,7),    (7,4),    (5,1),    (6,2),    (7,3)    )def cube():    glBegin(GL_LINES)    for x in lines:        for y in x:            glVertex3fv(sharps[y])    glEnd()def main():    pygame.init()    x=800    y=600    window=pygame.display.set_mode((x,y), DOUBLEBUF|OPENGL)    gluPerspective(45,(x/y),0.1,50.0)    glTranslatef(0.0,0.0,-5)    glRotatef(0,0,0,0)    true = True    while true:     for i in pygame.event.get():        if i.type==pygame.QUIT:            true=False     glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)     cube()     pygame.display.flip()     pygame.time.wait(10)try:    main()except Exception, e:    print e 

and the error

global name 'DOUBLEBUF' is not defined

i dont seem to understand where the problem lie, i mean it worked for the guy in youtube.Please help