[Pygui] Convert RGBA to BGRA using standard library?

[Sidney Markowitz]

I suppose it is obvious, but to be complete here is the code again with a few
lines I accidentally left out

import cStringIO
myrgba = "rgbaRGBA1234"

output = cStringIO.StringIO()
input = cStringIO.StringIO(myrgba)

c1 = input.read(1)
while c1:
    c2 = input.read(1)
    c3 = input.read(1)
    c4 = input.read(1)
    output.write(c3)
    output.write(c2)
    output.write(c1)
    output.write(c4)
    c1 = input.read(1)

mybgra = output.getvalue()