diff --git a/addons/web/static/lib/py.js/lib/py.js b/addons/web/static/lib/py.js/lib/py.js
index 382247c2745..3af06a8eb99 100644
--- a/addons/web/static/lib/py.js/lib/py.js
+++ b/addons/web/static/lib/py.js/lib/py.js
@@ -758,7 +758,7 @@ var py = {};
             if (value === placeholder) {
                 this._value = 0; return;
             }
-            if (py.PYisInstance(value, py.float)) {
+            if (py.PY_isInstance(value, py.float)) {
                 this._value = value._value;
             }
             if (py.PY_isInstance(value, py.object) && '__float__' in value) {