Function eliminate_fee_excess

fn eliminate_fee_excess<'a>(
    (fee_token_l, fee_excess_l): (&'a TokenId, &'a Signed<Fee>),
    (fee_token_m, fee_excess_m): (&'a TokenId, &'a Signed<Fee>),
    (fee_token_r, fee_excess_r): (&'a TokenId, &'a Signed<Fee>),
) -> Result<((&'a TokenId, Signed<Fee>), (&'a TokenId, Signed<Fee>)), String>

Eliminate a fee excess, either by combining it with one to the left/right, or by checking that it is zero.

https://github.com/MinaProtocol/mina/blob/2ee6e004ba8c6a0541056076aab22ea162f7eb3a/src/lib/mina_base/fee_excess.ml#L200