Added comment for param: limit (int).

Author: Vegard Botnen

binance/depthcache.py

@@ -131,6 +131,8 @@ def __init__(self, client, symbol, callback=None, refresh_interval=_default_refr
         :type callback: function
         :param refresh_interval: Optional number of seconds between cache refresh, use 0 or None to disable
         :type refresh_interval: int
+        :param limit: Optional number of orders to get from orderbook
+        :type limit: int
 
         """
         self._client = client