add serializer class dummy

src/utilities/feedfile.py

@@ -2,7 +2,7 @@ __author__ = 'stubbfel'
 
 import feedparser
 from utilities.textfile import TextFile
-
+from utilities.serializer import Serializer
 
 class FeedFile(TextFile):
 
@@ -21,11 +21,18 @@ class FeedFile(TextFile):
         feed_str = self.read_text_file()
         return feedparser.parse(feed_str)
 
-    def write_feed_file(self, feed, serializer):
+    def write_feed_file(self, feed, serializer=None):
+        """
+        method write a feedparpser object to a text file. It use a certain serializer or the default serializer
+        if type of the serializer is none
+        :param feed: expetc FeedparserDict
+        :param serializer: None or a subclass of Serializer
+        """
         assert isinstance(feed, feedparser.FeedParserDict)
 
         if serializer is None:
-            feed_string = str(feed)
+            serializer = Serializer()
+            feed_string = serializer.serialize(feed)
         else:
             feed_string = serializer.toString(feed)
         self.write_text_file(feed_string)

src/utilities/serializer.py

@@ -0,0 +1,14 @@
+__author__ = 'stubbfel'
+
+
+class Serializer():
+
+    def serialize(self, dict_object):
+        """
+        method convert i dict to a string.
+        this method should be override by any subclasses
+        :param dict_object: object wich his to bee convert to a string
+        :return: rhe string reprasention of the dict_object
+        """
+        assert isinstance(dict_object, dict)
+        return  str(dict_object)