diff --git a/src/drivers.ts b/src/drivers.ts
index fb94c72..549a332 100644
--- a/src/drivers.ts
+++ b/src/drivers.ts
@@ -23,27 +23,29 @@ export { Zibal } from './drivers/zibal';
 interface ConfigMap {
   idpay: IdPayAPI.Config;
   nextpay: NextPayAPI.Config;
+  payir: PayirAPI.Config;
   sadad: SadadAPI.Config;
   saman: SamanAPI.Config;
   zarinpal: ZarinpalAPI.Config;
   zibal: ZibalAPI.Config;
-  payir: PayirAPI.Config;
 }
 
 export type ConfigObject = Partial<ConfigMap>;
 
+export type DriverName = keyof ConfigMap;
+
 const drivers = {
   idpay: IdPay,
   nextpay: NextPay,
+  payir: Payir,
   sadad: Sadad,
   saman: Saman,
   zarinpal: Zarinpal,
   zibal: Zibal,
-  payir: Payir,
 };
 
 export const getPaymentDriver = <Driver extends BaseDriver>(
-  driverName: keyof ConfigMap,
+  driverName: DriverName,
   config: Parameters<Driver['setConfig']>[0]
 ): Driver => {
   if (!drivers[driverName]) {
diff --git a/src/drivers/idpay/api.ts b/src/drivers/idpay/api.ts
index 0d5ae99..545b88e 100644
--- a/src/drivers/idpay/api.ts
+++ b/src/drivers/idpay/api.ts
@@ -3,6 +3,7 @@ import { BaseReceipt, ErrorList, LinksObject, tBaseRequestOptions, tBaseVerifyOp
 
 /*
  * IDPay's API
+ * Currency: IRR
  */
 
 export const links: LinksObject = {
diff --git a/src/drivers/nextpay/api.ts b/src/drivers/nextpay/api.ts
index 36f7399..e695e32 100644
--- a/src/drivers/nextpay/api.ts
+++ b/src/drivers/nextpay/api.ts
@@ -3,6 +3,7 @@ import { BaseReceipt, ErrorList, LinksObject, tBaseRequestOptions, tBaseVerifyOp
 
 /*
  * Zarinpal's API
+ * Currency: IRT
  */
 
 export const links: LinksObject = {
diff --git a/src/drivers/payir/api.ts b/src/drivers/payir/api.ts
index 3d2d0d5..c9a768f 100644
--- a/src/drivers/payir/api.ts
+++ b/src/drivers/payir/api.ts
@@ -3,6 +3,7 @@ import { BaseReceipt, ErrorList, LinksObject, tBaseRequestOptions, tBaseVerifyOp
 
 /*
  * Payir's API
+* Currency: IRR
  */
 
 export const links: LinksObject = {
diff --git a/src/drivers/sadad/api.ts b/src/drivers/sadad/api.ts
index 950554b..2e9d812 100644
--- a/src/drivers/sadad/api.ts
+++ b/src/drivers/sadad/api.ts
@@ -3,6 +3,7 @@ import { BaseReceipt, ErrorList, LinksObject, tBaseRequestOptions, tBaseVerifyOp
 
 /*
  * Sadad's API
+ * Currency: IRR
  * link: https://sadadpsp.ir/file/attach/202002/654.pdf
  */
 
diff --git a/src/drivers/saman/api.ts b/src/drivers/saman/api.ts
index cac2868..de876f2 100644
--- a/src/drivers/saman/api.ts
+++ b/src/drivers/saman/api.ts
@@ -3,6 +3,7 @@ import { BaseReceipt, ErrorList, LinksObject, tBaseRequestOptions, tBaseVerifyOp
 
 /*
  * Saman's API
+ * Currency: IRR
  */
 
 export const links: LinksObject = {
diff --git a/src/drivers/zarinpal/api.ts b/src/drivers/zarinpal/api.ts
index 91c97fa..5178364 100644
--- a/src/drivers/zarinpal/api.ts
+++ b/src/drivers/zarinpal/api.ts
@@ -3,6 +3,7 @@ import { BaseReceipt, ErrorList, LinksObject, tBaseRequestOptions, tBaseVerifyOp
 
 /*
  * Zarinpal's API
+ * Currency: IRR
  */
 
 export const links: LinksObject = {
diff --git a/src/drivers/zibal/api.ts b/src/drivers/zibal/api.ts
index 978b18f..029f777 100644
--- a/src/drivers/zibal/api.ts
+++ b/src/drivers/zibal/api.ts
@@ -3,6 +3,7 @@ import { BaseReceipt, ErrorList, LinksObject, tBaseRequestOptions, tBaseVerifyOp
 
 /*
  * Zibal's API
+ * Currency: IRR
  */
 
 export const links: LinksObject = {