Change the result function of the GetAttribute class to return self.

As this function does not return a "valid" result I think that is better that it returns a GetAttribute object instead of a list that can confuse the user that it is a real result.

Change-Id: Ia4d5384dc6b84f66a657d585684a1bc0e8fbb0a4

toscaparser/functions.py

@@ -131,7 +131,7 @@ class GetAttribute(Function):
         self._find_node_template_containing_attribute()
 
     def result(self):
-        return self.args
+        return self
 
     def get_referenced_node_template(self):
         """Gets the NodeTemplate instance the get_attribute function refers to.