Index: patch.py
===================================================================
--- patch.py	(revision 203)
+++ patch.py	(working copy)
@@ -166,17 +166,27 @@
     self.desc=''
     self.text=[]
 
-#  def apply(self, estream):
-#    """ write hunk data into enumerable stream
-#        return strings one by one until hunk is
-#        over
-#
-#        enumerable stream are tuples (lineno, line)
-#        where lineno starts with 0
-#    """
-#    pass
+  def apply(self, estream):
+    """ write hunk data into enumerable stream
+        return strings one by one until hunk is
+        over
 
+        enumerable stream are tuples (lineno, line)
+        where lineno starts with 0
+    """
+    if type(estream) is not type([]):
+      return estream
+    header = "@@ -{0},{1} +{2},{3} @@{4}".format(self.startsrc, self.linessrc,
+                                                 self.starttgt, self.linestgt,
+                                                 self.desc)
+    estream.append((0, header + '\n'))
+    estream.extend(enumerate(self.text, 1))
+    return estream
 
+  def __str__(self):
+    return ''.join([line for _, line in self.apply([])])
+
+
 class Patch(object):
   """ Patch for a single file """
   def __init__(self):