Removed unnecessary target in SmoothnessOperator

nifty/operators/smoothness_operator/smoothness_operator.py

@@ -59,10 +59,6 @@ class SmoothnessOperator(EndomorphicOperator):
 
     # ---Mandatory properties and methods---
 
-    @property
-    def target(self):
-        return self._domain
-
     @property
     def domain(self):
         return self._domain