diff --git a/stablepay-sdk/src/core/Wallet.js b/stablepay-sdk/src/core/Wallet.js
index 0c666ef..f4a410a 100644
--- a/stablepay-sdk/src/core/Wallet.js
+++ b/stablepay-sdk/src/core/Wallet.js
@@ -1,3 +1,6 @@
+import { createWalletClient, custom } from 'viem';
+import { mainnet, sepolia } from 'viem/chains';
+
 export class Wallet {
   constructor(chainId) {
     this.chainId = chainId;
@@ -34,7 +37,11 @@ export class Wallet {
       11155111: sepolia,
       // Add other chains as needed
     };
-    return chains[chainId];
+    const chain = chains[chainId];
+      if (!chain) {
+        throw new Error(`Unsupported chainId: ${chainId}`);
+      }
+      return chain;
   }
 
   async disconnect() {
@@ -49,4 +56,4 @@ export class Wallet {
   getAccount() {
     return this.account;
   }
-}
\ No newline at end of file
+}