def w3_tx(self):
        """
        :return: Web3 contract tx prepared for `call`, `transact` or `buildTransaction`
        """
        safe_contract = get_safe_contract(self.w3, address=self.safe_address)
        return safe_contract.functions.execTransaction(
            self.to,
            self.value,
            self.data,
            self.operation,
            self.safe_tx_gas,
            self.data_gas,
            self.gas_price,
            self.gas_token,
            self.refund_receiver,
            self.signatures)
:return: Web3 contract tx prepared for `call`, `transact` or `buildTransaction`