fn a(
env: soroban_sdk::Env,
a: soroban_sdk::Vec<
(soroban_sdk::Address, soroban_sdk::Symbol, soroban_sdk::Vec),
>,
) fn exec_op(
env: soroban_sdk::Env,
a: soroban_sdk::Address,
b: soroban_sdk::Address,
c: i128,
d: i128,
)