diff --git a/bin/addons/base/module/module.py b/bin/addons/base/module/module.py
index 22e47ee8301..f05b2c382d2 100644
--- a/bin/addons/base/module/module.py
+++ b/bin/addons/base/module/module.py
@@ -445,7 +445,7 @@ class module(osv.osv):
             categs = categs[1:]
         self.write(cr, uid, [id], {'category_id': p_id})
 
-    def update_translations(self, cr, uid, ids, filter_lang=None, context={}):
+    def update_translations(self, cr, uid, ids, filter_lang=None, context=None):
         logger = logging.getLogger('i18n')
         if not filter_lang:
             pool = pooler.get_pool(cr.dbname)
diff --git a/bin/tools/translate.py b/bin/tools/translate.py
index 5fcae3dd01a..97bac00a359 100644
--- a/bin/tools/translate.py
+++ b/bin/tools/translate.py
@@ -774,7 +774,7 @@ def trans_generate(lang, modules, dbname=None):
     cr.close()
     return out
 
-def trans_load(db_name, filename, lang, strict=False, verbose=True, context={}):
+def trans_load(db_name, filename, lang, strict=False, verbose=True, context=None):
     logger = logging.getLogger('i18n')
     try:
         fileobj = open(filename,'r')
@@ -788,10 +788,12 @@ def trans_load(db_name, filename, lang, strict=False, verbose=True, context={}):
             logger.error("couldn't read translation file %s", filename)
         return None
 
-def trans_load_data(db_name, fileobj, fileformat, lang, strict=False, lang_name=None, verbose=True, context={}):
+def trans_load_data(db_name, fileobj, fileformat, lang, strict=False, lang_name=None, verbose=True, context=None):
     logger = logging.getLogger('i18n')
     if verbose:
         logger.info('loading translation file for language %s', lang)
+    if context is None:
+        context = {}
     pool = pooler.get_pool(db_name)
     lang_obj = pool.get('res.lang')
     trans_obj = pool.get('ir.translation')