fix(readme): correct account balance example to use valid SDK APIs (#1253)

Signed-off-by: Parv <[email protected]>

Author: parvninama

CHANGELOG.md

@@ -111,6 +111,7 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 
 ### Fixed
 
+- Fixed the README account balance example to use correct SDK APIs and provide a runnable testnet setup. (#1250)
 - Fix token association verification in `token_airdrop_transaction.py` to correctly check if tokens are associated by using `token_id in token_balances` instead of incorrectly displaying zero balances which was misleading (#[815])
 - Fixed inactivity bot workflow not checking out repository before running (#964)
 - Fixed the topic_message_query integarion test

README.md

@@ -14,6 +14,7 @@ A Python SDK for interacting with the Hedera Hashgraph platform.
 ```bash
 pip install --upgrade pip
 pip install hiero-sdk-python
+pip install python-dotenv
 ```
 
 ### Environment Configuration
@@ -30,14 +31,22 @@ A sample file is provided: [.env.example](.env.example)
 ### Basic Usage
 
 ```python
-from hiero_sdk_python import Client, AccountBalanceQuery
+import os
+from dotenv import load_dotenv
+from hiero_sdk_python import Network, Client, CryptoGetAccountBalanceQuery, AccountId, PrivateKey
 
 # Connect to testnet
-client = Client.for_testnet()
-client.set_operator(account_id, private_key)
+load_dotenv()
+network = Network("testnet")
+client = Client(network)
+
+operator_id = AccountId.from_string(os.getenv("OPERATOR_ID",""))
+operator_key = PrivateKey.from_string(os.getenv("OPERATOR_KEY",""))
+
+client.set_operator(operator_id, operator_key)
 
 # Query account balance
-balance = AccountBalanceQuery(account_id=account_id).execute(client)
+balance = CryptoGetAccountBalanceQuery(account_id=operator_id).execute(client)
 print(f"Balance: {balance.hbars} HBAR")
 ```