I have sample variables in cfmm sample code

local_indices = [
[0, 1, 2, 3], # TOKEN-0/TOKEN-1/TOKEN-2/TOKEN-3
[0, 1], # TOKEN-0/TOKEN-1
[1, 2], # TOKEN-1/TOKEN-2
[2, 3], # TOKEN-2/TOKEN-3
[2, 3] # TOKEN-2/TOKEN-3
]

reserves = list(map(np.array, [
[4, 4, 4, 4], # balancer with 4 assets in pool TOKEN-0, TOKEN-1, TOKEN-2, TOKEN-3 (4 TOKEN-0, 4 TOKEN-1, 4 TOKEN-2 & 4 TOKEN-3 IN POOL)
[10, 1], # uniswapV2 TOKEN-0/TOKEN-1 (10 TOKEN-0 & 1 TOKEN-1 IN POOL)
[1, 5], # uniswapV2 TOKEN-1/TOKEN-2 (1 TOKEN-1 & 5 TOKEN-2 IN POOL)
[40, 50], # uniswapV2 TOKEN-2/TOKEN-3 (40 TOKEN-2 & 50 TOKEN-3 IN POOL)
[10, 10] # constant_sum TOKEN-2/TOKEN-3 (10 TOKEN-2 & 10 TOKEN-3 IN POOL)
]))

fees = [
.998, # balancer fees
.997, # uniswapV2 fees
.997, # uniswapV2 fees
.997, # uniswapV2 fees
.999 # constant_sum fees
]

why constant_sum is 10, 10 ?