ARGB --> RGBA

bytelist = list(b'abcdabcdabcd')

splits = len(x) // 4
arraysplits = []
current = 0
for i in range(1, splits+1):
    arraysplits.append((current, 4*i))
    current = 4*i

splitbytes = []
for idx in arraysplits:
    splitbytes.append(bytelist[idx[0]:idx[1]])

rgbalist = []
for argb in splitbytes:
    rgba = argb[1:] + [argb[0]]
    rgbalist.append(rgba)

finalbytes = bytearray()
for rgba in rgbalist:
    for byte in rgba:
        finalbytes.append(byte)

finalbytes = bytes(finalbytes)