diff --git a/ast_generator/ast_generator.py b/ast_generator/ast_generator.py
index 7e6000b..c23e64f 100644
--- a/ast_generator/ast_generator.py
+++ b/ast_generator/ast_generator.py
@@ -357,20 +357,23 @@ class AstGenerator:
         self.current_ast_element = parent
 
     def generate_unary(self, op, op_type=ANY_TYPE):
+        """
+        @brief Generate a unary operation
+
+        @param op_type: the type of the expression
+        """
         parent = self.current_ast_element
         args = [
             ("op", op),
             ("type", op_type),
         ]
-        element = build_xml_element(args, name=GAZ_UNARY_OPERATOR_TAG)
-        self.current_ast_element.append(element)
-        self.current_ast_element = element
+        self.make_element(GAZ_UNARY_OPERATOR_TAG, args)
 
         self.generate_xhs(GAZ_RHS_TAG, op_type)
 
         self.current_ast_element = parent
 
-    def generate_routine_call(self):
+    def generate_routine_call(self): # we should generate a test case with arbitrary number of args
         pass
 
     def generate_conditional(self):