how to use this signature interface

[Liu-Zhiying]

the interface is "pub(crate) fn sign_tezos_tx_raw(param: &SignParam, keystore: &mut Keystore) -> Result<Vec>".
I do not know the usage of "TezosRawTxIn" structure.
in fact there is no declaration of this structure is its field "raw_data"
how to convert my data to the string.
the interface is in "token-core-dev/tcx/src/handler.rs"
the define of the structure is in "token-core-dev/tcx-tezos/src/transaction.rs"