diff --git a/source/rafcon/mvc/selection.py b/source/rafcon/mvc/selection.py
index <HASH>..<HASH> 100644
--- a/source/rafcon/mvc/selection.py
+++ b/source/rafcon/mvc/selection.py
@@ -67,6 +67,9 @@ class Selection(Observable):
     def __len__(self):
         return len(self.__selected)
 
+    def __contains__(self, item):
+        return item in self.__selected
+
     def __getitem__(self, key):
         return [s for s in self.__selected][key]
Add __contains__ method to Selection class

With this, one can write "if model in selection" instead of having to
write "if model in selection.get_all()"