a = BCD[0]
b = BCD[1]
c = BCD[2]
d = BCD[3]
e = BCD[4]
f = BCD[5]
g = BCD[6]
h = BCD[7]
i = BCD[8]
j = BCD[9]
k = BCD[10]
m = BCD[11]

si = SelectableInt(0b010000000000, 12) # 0x400
rv = concat(a, b, c, d, e, f, g, h, i, j, k, m)
bits = [si[bit] for bit in range(12)]
print(si, rv, concat(*bits))