Bug fix

forgot a pair of parens when needed

src/python/bindings_docstring_keyed.hpp

@@ -54,8 +54,8 @@ namespace sisso
                 inline std::string get_postfix_term(){return this->get_override("get_postfix_term")();}
                 inline void update_add_sub_leaves(std::map<std::string, int>& add_sub_leaves, int pl_mn, int& expected_abs_tot){this->get_override("update_add_sub_leaves");}
                 inline void update_div_mult_leaves(std::map<std::string, double>& div_mult_leaves, double fact, double& expected_abs_tot){this->get_override("update_div_mult_leaves");}
-                inline int n_feats(){return this->get_override("n_feats");}
-                inline std::shared_ptr<Node> feat(int ind){return this->get_override("feat");}
+                inline int n_feats(){return this->get_override("n_feats")();}
+                inline std::shared_ptr<Node> feat(int ind){return this->get_override("feat")();}
             };
             /**
              * @brief struct used wrap an OperatorNode object for conversion
@@ -105,7 +105,6 @@ namespace sisso
                     .def("unit", py::pure_virtual(&OperatorNode<N>::unit), "@DocString_op_node_unit@")
                     .add_property("n_feats", &OperatorNode<N>::n_feats, "@DocString_op_node_n_feats@")
                     .add_property("feat", &OperatorNode<N>::feat, "@DocString_op_node_feat@")
-
                 ;
             }