Fix typo causing parse error in binary search tree traversal methods

Author: neptunius

source/binarytree.py

@@ -162,7 +162,7 @@ def items_in_order(self):
         items = []
         if not self.is_empty():
             # Traverse tree in-order from root, appending each node's item
-            self._traverse_in_order_recursive(self.root, items.append):
+            self._traverse_in_order_recursive(self.root, items.append)
         # Return in-order list of all items in tree
         return items
 
@@ -190,7 +190,7 @@ def items_pre_order(self):
         items = []
         if not self.is_empty():
             # Traverse tree pre-order from root, appending each node's item
-            self._traverse_pre_order_recursive(self.root, items.append):
+            self._traverse_pre_order_recursive(self.root, items.append)
         # Return pre-order list of all items in tree
         return items
 
@@ -218,7 +218,7 @@ def items_post_order(self):
         items = []
         if not self.is_empty():
             # Traverse tree post-order from root, appending each node's item
-            self._traverse_post_order_recursive(self.root, items.append):
+            self._traverse_post_order_recursive(self.root, items.append)
         # Return post-order list of all items in tree
         return items
 
@@ -246,7 +246,7 @@ def items_level_order(self):
         items = []
         if not self.is_empty():
             # Traverse tree level-order from root, appending each node's item
-            self._traverse_level_order_iterative(self.root, items.append):
+            self._traverse_level_order_iterative(self.root, items.append)
         # Return level-order list of all items in tree
         return items