Added example of MARKET order with price=None

bfxapi/examples/rest/create_order.py

@@ -4,6 +4,7 @@ import asyncio
 import time
 sys.path.append('../../../')
 from bfxapi import Client
+from bfxapi.models import OrderType
 
 API_KEY=os.getenv("BFX_KEY")
 API_SECRET=os.getenv("BFX_SECRET")
@@ -15,7 +16,7 @@ bfx = Client(
 )
 
 async def create_order():
-  response = await bfx.rest.submit_order("tBTCUSD", 10, 0.1)
+  response = await bfx.rest.submit_order(symbol="tBTCUSD", amount=10, price=None, market_type=OrderType.MARKET)
   # response is in the form of a Notification object
   for o in response.notify_info:
     # each item is in the form of an Order object