Add the ability to submit a single leg option order

ibkr/client.py

@@ -79,6 +79,20 @@ class Client:
         self.ib.qualifyContracts(option_contract)
         return option_contract
     
+    def submit_option_order(self, leg: OptionLeg, quantity: int):
+        option_contract = self.get_option_contract(leg)
+        contract = Contract()
+        contract.conId = option_contract.conId
+        contract.exchange = SMART
+
+        order = Order()
+        order.action = BUY
+        order.orderType = 'MKT'  # TODO: Support limit orders.
+        order.totalQuantity = quantity
+        order.transmit = True
+
+        return self.ib.placeOrder(contract, order)
+
     def submit_combo_option_order(self, legs: List[OptionLeg], quantity: int) -> Trade:
         combo_legs = []
         for leg in legs: