def METHOD_NAME(self, processing_values):
    res = super().METHOD_NAME(processing_values)
    if self.provider_code != "redsys":
        return res
    redsys_values = dict(processing_values)
    merchant_parameters = self.provider_id._prepare_merchant_parameters(
        processing_values
    )
    redsys_values.update(
        {
            "api_url": self.provider_id._redsys_get_api_url(),
            "Ds_SignatureVersion": str(self.provider_id.redsys_signature_version),
            "Ds_MerchantParameters": merchant_parameters,
            "Ds_Signature": self.provider_id.sign_parameters(
                self.provider_id.redsys_secret_key, merchant_parameters
            ),
        }
    )
    return redsys_values