[Add] send_orders and cancel_orders function

vnpy/trader/gateway.py

@@ -3,7 +3,7 @@
 """
 
 from abc import ABC, abstractmethod
-from typing import Any
+from typing import Any, Sequence
 from copy import copy
 
 from vnpy.event import Event, EventEngine
@@ -210,6 +210,29 @@ class BaseGateway(ABC):
         """
         pass
 
+    def send_orders(self, reqs: Sequence[OrderRequest]):
+        """
+        Send a batch of orders to server.
+        Use a for loop of send_order function by default. 
+        Reimplement this function if batch order supported on server.
+        """
+        vt_orderids = []
+
+        for req in reqs:
+            vt_orderid = self.send_order(req)
+            vt_orderids.append(vt_orderid)
+
+        return vt_orderids
+
+    def cancel_orders(self, reqs: Sequence[CancelRequest]):
+        """
+        Cancel a batch of orders to server.
+        Use a for loop of cancel_order function by default. 
+        Reimplement this function if batch cancel supported on server.
+        """
+        for req in reqs:
+            self.cancel_order(req)
+
     @abstractmethod
     def query_account(self):
         """