--- a/src/tools/common/data_format.py	Sun Sep 25 16:07:44 2016 +0200
+++ b/src/tools/common/data_format.py	Sun Sep 25 19:16:25 2016 +0200
@@ -31,7 +31,7 @@
     iteration stop at first missing increment
     Empty values are possible
     @param name(unicode): name of the key
-    @param mb_data (dict): dictionary with the serialised list
+    @param dict_(dict): dictionary with the serialised list
     @param pop(bool): if True, remove the value from dict
     @return iter: iterate through the deserialised list
     """
@@ -79,3 +79,24 @@
             raise exceptions.ConflictError
         dict_[key] = value
     return dict
+
+def getSubDict(name, dict_, sep=u'_'):
+    """get a sub dictionary from a serialised dictionary
+
+    look for keys starting with name, and create a dict with it
+    eg.: if "key" is looked for, {'html': 1, 'key_toto': 2, 'key_titi': 3} will return:
+        {None: 1, toto: 2, titi: 3}
+    @param name(unicode): name of the key
+    @param dict_(dict): dictionary with the serialised list
+    @param sep(unicode): separator used between name and subkey
+    @return iter: iterate through the deserialised items
+    """
+    for k,v in dict_.iteritems():
+        if k.startswith(name):
+            if k == name:
+                yield None, v
+            else:
+                if k[len(name)] != sep:
+                    continue
+                else:
+                    yield k[len(name)+1:], v