return_values/return_values_ssa: Remove dupplicate

slither/core/declarations/function.py

@@ -482,7 +482,7 @@ class Function(ChildContract, SourceMapping):
             return_values = list()
             returns = [n for n in self.nodes if n.type == NodeType.RETURN]
             [return_values.extend(ir.values) for node in returns for ir in node.irs if isinstance(ir, Return)]
-            self._return_values = return_values
+            self._return_values = list(set(return_values))
         return self._return_values
 
     @property
@@ -497,7 +497,7 @@ class Function(ChildContract, SourceMapping):
             return_values_ssa = list()
             returns = [n for n in self.nodes if n.type == NodeType.RETURN]
             [return_values_ssa.extend(ir.values) for node in returns for ir in node.irs_ssa if isinstance(ir, Return)]
-            self._return_values_ssa = return_values_ssa
+            self._return_values_ssa = list(set(return_values_ssa))
         return self._return_values_ssa
 
     # endregion