V Token Interface

fn total_debt_of(&self, underlying_asset: AccountId) -> Balance;

fn user_debt_of(&self, underlying_asset: AccountId, user: AccountId) -> Balance;

fn transfer_debt_from_to(
    &mut self,
    underlying_asset: AccountId,
    from: AccountId,
    to: AccountId,
    amount: Balance,
) -> Result<(Balance, Balance), LendingPoolError>;