core.py_patch

--- /usr/local/lib/python2.7/dist-packages/atom/core.py_old	2012-06-27 16:42:36.627780827 +0300
+++ /usr/local/lib/python2.7/dist-packages/atom/core.py	    2012-06-27 16:42:28.995780322 +0300
@@ -346,10 +346,10 @@
       else:
         tree.text = self.text.decode(encoding)
 
-  def to_string(self, version=1, encoding=None, pretty_print=None):
+  def to_string(self, version=1, encoding=STRING_ENCODING, pretty_print=None):
     """Converts this object to XML."""
 
-    tree_string = ElementTree.tostring(self._to_tree(version, encoding))
+    tree_string = ElementTree.tostring(self._to_tree(version, encoding), encoding)
 
     if pretty_print and xmlString is not None:
         return xmlString(tree_string).toprettyxml()