Made the filename an attribute of the address book object, so it is DRY, also so that the caller can get the filename

Author: jeffsilverm

week-09/code/address_book/address_book_data.py

@@ -13,11 +13,16 @@ class AddressBook(object):
     """
     def __init__(self):
         self.book = []
+        self.filename = "a_book.json"
 
-    def save_to_file(self, filename='a_book.json'):
+    def save_to_file(self, filename=None):
+	if filename != None :
+            self.filename = filename
         json.dump(self.book, open(filename, 'wb'), indent=4 )
 
-    def load_from_file(self, filename='a_book.json'):
+    def load_from_file(self, filename=None):
+	if filename != None :
+            self.filename = filename
         self.book = json.load( open(filename, 'rb') )