Is there a way to sign a transaction with only 3 fields as parameters?

[fabriziogianni7]

Hello, I'm trying to replicate this flow link where a notary has to sign a custom transaction which has only 3 parameters: client address, datacap to remove,and ID.t The lotus CLI just call [rpc.walletSign(...) ](https://github.com/filecoin-project/lotus/blob/422f66776fa07827f2cfa9d2f8142ef29dcd2a95/cli/filplus.go#L375 it just output the signed transaction. In this case, I'm not building a message with to, value, gasfee and so on. is there a method to sign this message using just custom parameters? thank you very much for the support.

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