Created a method decorator to change temporarily the value of an attribute to the instance

greenmine/base/decorators.py

@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+from functools import wraps
+
+def change_instance_attr(name, new_value):
+    """
+    Change the attribute value temporarily for a new one. If it raise an AttributeError (if the
+    instance hasm't the attribute) the attribute will not be changed.
+    """
+    def change_instance_attr(fn):
+        @wraps(fn)
+        def wrapper(instance, *args, **kwargs):
+            try:
+                old_value = instance.__getattribute__(name)
+                changed = True
+            except AttributeError:
+                changed = False
+
+            if changed:
+                instance.__setattr__(name, new_value)
+
+            ret =  fn(instance, *args, **kwargs)
+
+            if changed:
+                instance.__setattr__(name, old_value)
+
+            return ret
+        return wrapper
+    return change_instance_attr
+