Function propose_shielding 

pub fn propose_shielding<DbT, ParamsT, InputsT, ChangeT, CommitmentTreeErrT>(
    wallet_db: &mut DbT,
    params: &ParamsT,
    input_selector: &InputsT,
    change_strategy: &ChangeT,
    shielding_threshold: Zatoshis,
    from_addrs: &[TransparentAddress],
    to_account: <DbT as InputSource>::AccountId,
    confirmations_policy: ConfirmationsPolicy,
    output_filter: CoinbaseFilter,
    lock_inputs: Option<LockRequest>,
) -> Result<Proposal<ChangeT::FeeRule, Infallible>, ProposeShieldingErrT<DbT, CommitmentTreeErrT, InputsT, ChangeT>>
where
    ParamsT: Parameters,
    DbT: WalletWrite + InputSource<Error = <DbT as WalletRead>::Error>,
    InputsT: ShieldingSelector<InputSource = DbT>,
    ChangeT: ChangeStrategy<MetaSource = DbT>,

Available on crate feature transparent-inputs only.

Constructs a proposal to shield all of the funds belonging to the provided set of addresses.

The output_filter parameter controls which transparent outputs are eligible for inclusion in the proposal. See CoinbaseFilter for details.

When lock_inputs is Some(request), the inputs selected by the proposal are locked on behalf of the request’s owner until target_height + request.for_blocks() to prevent concurrent proposals from selecting them; when None, no locking is performed. See propose_transfer for the full semantics and concurrency behavior.