Merge pull request PegasusWang#12 from DA-southampton/master

Update bag_adt.py

Author: PegasusWang

docs/01_抽象数据类型和面向对象编程/bag_adt.py

@@ -8,7 +8,7 @@ def __init__(self, maxsize=10):
         self._items = list()
 
     def add(self, item):
-        if len(self) > self.maxsize:
+        if len(self) >= self.maxsize:
             raise Exception('Full')
         self._items.append(item)