pub trait UpdatableVault<T: Config> {
// Required methods
fn increase_issued(&mut self, tokens: &Amount<T>) -> DispatchResult;
fn increase_to_be_issued(&mut self, tokens: &Amount<T>) -> DispatchResult;
fn increase_to_be_redeemed(&mut self, tokens: &Amount<T>) -> DispatchResult;
fn decrease_issued(&mut self, tokens: &Amount<T>) -> DispatchResult;
fn decrease_to_be_issued(&mut self, tokens: &Amount<T>) -> DispatchResult;
fn decrease_to_be_redeemed(&mut self, tokens: &Amount<T>) -> DispatchResult;
}