Add documentation for reading a single price account (#18)

* Add documentation for reading a single price account

* PR comments

Co-authored-by: Jayant Krishnamurthy <[email protected]>

Author: jayantk

README.md

@@ -52,8 +52,9 @@ PythPriceType.PRICE 4.23125 p/m 0.0019500000000000001
 ...
 ```
 
-The library also includes an asynchronous API that updates the prices using a websocket subscription or account polling.
-See `examples/dump.py` for a more detailed usage example.
+The `examples` directory includes some example applications that demonstrate how to use this library:
+* `examples/dump.py` is a detailed usage example that demonstrates the asynchronous API to update prices using a websocket subscription or account polling.
+* `examples/read_one_price_feed.py` shows how to read the price of a single price feed using its account key.
 
 Developer Setup
 ---------------

examples/read_one_price_feed.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+
+import asyncio
+
+from pythclient.pythaccounts import PythPriceAccount
+from pythclient.solana import SolanaClient, SolanaPublicKey, SOLANA_DEVNET_HTTP_ENDPOINT, SOLANA_DEVNET_WS_ENDPOINT
+
+async def get_price():
+    # devnet DOGE/USD price account key (available on pyth.network website)
+    account_key = SolanaPublicKey("4L6YhY8VvUgmqG5MvJkUJATtzB2rFqdrJwQCmFLv4Jzy")
+    solana_client = SolanaClient(endpoint=SOLANA_DEVNET_HTTP_ENDPOINT, ws_endpoint=SOLANA_DEVNET_WS_ENDPOINT)
+    price: PythPriceAccount = PythPriceAccount(account_key, solana_client)
+
+    await price.update()
+    # Sample output: "DOGE/USD is 0.141455 ± 7.4e-05"
+    print("DOGE/USD is", price.aggregate_price, "±", price.aggregate_price_confidence_interval)
+
+asyncio.run(get_price())