diff -r fdaa0e4b7eaf -r 7c23b7de2b8d migration.py
--- a/migration.py	Fri Sep 11 14:28:06 2015 +0200
+++ b/migration.py	Fri Sep 11 14:52:09 2015 +0200
@@ -16,6 +16,7 @@
 # You should have received a copy of the GNU Lesser General Public License along
 # with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
 """utilities for instances migration"""
+from __future__ import print_function
 
 __docformat__ = "restructuredtext en"
 
@@ -49,7 +50,7 @@
     assert fromversion <= toversion, (fromversion, toversion)
     if not exists(directory):
         if not quiet:
-            print directory, "doesn't exists, no migration path"
+            print(directory, "doesn't exists, no migration path")
         return []
     if fromversion == toversion:
         return []
@@ -93,9 +94,9 @@
             stream = open(scriptpath)
             scriptcontent = stream.read()
             stream.close()
-            print
-            print scriptcontent
-            print
+            print()
+            print(scriptcontent)
+            print()
         else:
             return True
 
@@ -240,7 +241,7 @@
         # avoid '_' to be added to builtins by sys.display_hook
         def do_not_add___to_builtins(obj):
             if obj is not None:
-                print repr(obj)
+                print(repr(obj))
         sys.displayhook = do_not_add___to_builtins
         local_ctx = self._create_context()
         try:
@@ -519,9 +520,9 @@
                     elif op == None:
                         continue
                     else:
-                        print ('unable to handle %s in %s, set to `%s %s` '
-                               'but currently up to `%s %s`' %
-                               (cube, source, oper, version, op, ver))
+                        print('unable to handle %s in %s, set to `%s %s` '
+                              'but currently up to `%s %s`' %
+                              (cube, source, oper, version, op, ver))
             # "solve" constraint satisfaction problem
             if cube not in self.cubes:
                 self.errors.append( ('add', cube, version, source) )
@@ -533,4 +534,4 @@
                 elif oper is None:
                     pass # no constraint on version
                 else:
-                    print 'unknown operator', oper
+                    print('unknown operator', oper)