In section 3.2.6, in the second code section the GLSL for the fragment shader:

varying vec4 v_color;
void main()
{
  gl_FragColor = color;
}

I think it should be gl_FragColor = v_color
I'm 100% new to opengl, and kinda new to python, this tripped me up for a while.

I think I have a slightly better sense of declaring input and output arguments to shaders look like (not exactly though) after having fiddled with that code until it worked.

I would have been able to proceed if the code worked though. :)